The king is left alone on the chessboard. In spite of this loneliness, he doesn't lose heart, because he has business of national importance. For example, he has to pay an official visit to square *t*. As the king is not in habit of wasting his time, he wants to get from his current position *s* to square *t* in the least number of moves. Help him to do this.

In one move the king can get to the square that has a common side or a common vertex with the square the king is currently in (generally there are 8 different squares he can move to).
The first line contains the chessboard coordinates of square *s*, the second line — of square *t*.

Chessboard coordinates consist of two characters, the first one is a lowercase Latin letter (from a to h), the second one is a digit from 1 to 8.
notation = ['a','b','c','d','e','f','g','h']
def left(x):
    for let in range(1,7): #cannot be a or h
        if notation[let+1]==x:
            return notation[let]
def right(x):
    for let in range(7):
        if notation[let]==x:
            return notation[let+1]
def u(x,y):
    return [x,y+1]
def d(x,y):
    return [x,y-1]
def l(x,y):
    return [left(x),y]
def r(x,y):
    return [right(x),y]
#lu ld ru rd
def lu(x,y):
    return [left(x),y+1]
def ld(x,y):
    return [left(x),y-1]
def ru(x,y):
    return [right(x),y+1]
def rd(x,y):
    return [right(x),y-1]
def sameColumn(a,b):
    if a[0]==b[0]:
        return True
    return False
def sameRow(a,b):
    if a[1]==b[1]:
        return True
    return False
def lexDistance(leta,letb):
    d = {'a':1,'b':2,'c':3,'d':4,'e':5,'f':6,'g':7,'h':8}
    s = 0
    for k,v in d:
        if k==leta[0]:
            s-=v
        elif k==letb[0]:
            n+=v
    return abs(s)

a = input()
b = input()
a,b = ' '.join(a).split(),' '.join(b).split()
b[1] = int(b[1])
c = 0
moves = []
over = False
if a==b:
    print(0)
elif sameColumn(a,b):
    print(abs(int(a[1]),int(b[1])))
    #print shortest path
elif sameRow(a,b):
    print(lexDistance(a,b))
    #print shortest path
else: #diagonal
    if ord(a[0])<ord(b[0]) and int(a[1])<int(b[1]):
        while a[0]!=b[0] and int(a[1])!=int(b[1]):
            a = ru(a[0],int(a[1]))
            moves.append('RU')
            c+=1
            if a==b:
                print(c)
                for m in moves:
                    print(m)
                over = True
                break
        else:
            if not over:
                while int(a[1])==int(b[1]):
                    a = r(a[0],int(a[1]))
                    moves.append('R')
                    c+=1
                    if a==b:
                        print(c)
                        for m in moves:
                            print(m)
                        over = True
                        break
                while a[0]==b[0]:
                    a = u(a[0],int(a[1]))
                    moves.append('U')
                    c+=1
                    if a==b:
                        print(c)
                        for m in moves:
                            print(m)
                        over = True
                        break
    elif ord(a[0])<ord(b[0]) and int(a[1])>int(b[1]): #RD #R OR D
        while a[0]!=b[0] and int(a[1])!=int(b[1]):
            a = rd(a[0],int(a[1]))
            moves.append('RD')
            c+=1
            if a==b:
                print(c)
                for m in moves:
                    print(m)
                over = True
                break
        else:
            if not over:
                while int(a[1])==int(b[1]):
                    a = r(a[0],int(a[1]))
                    moves.append('R')
                    c+=1
                    if a==b:
                        print(c)
                        for m in moves:
                            print(m)
                        over = True
                        break
                while a[0]==b[0]:
                    a = d(a[0],int(a[1]))
                    moves.append('D')
                    c+=1
                    if a==b:
                        print(c)
                        for m in moves:
                            print(m)
                        over = True
                        break
    elif ord(a[0])>ord(b[0]) and int(a[1])>int(b[1]): #LD #L OR D
        while a[0]!=b[0] and int(a[1])!=int(b[1]):
            a = ld(a[0],int(a[1]))
            moves.append('LD')
            c+=1
            if a==b:
                print(c)
                for m in moves:
                    print(m)
                over = True
                break
        else:
            if not over:
                while int(a[1])==int(b[1]):
                    a = l(a[0],int(a[1]))
                    moves.append('L')
                    c+=1
                    if a==b:
                        print(c)
                        for m in moves:
                            print(m)
                        over = True
                        break
                while a[0]==b[0]:
                    a = d(a[0],int(a[1]))
                    moves.append('D')
                    c+=1
                    if a==b:
                        print(c)
                        for m in moves:
                            print(m)
                        over = True
                        break
    elif ord(a[0])>ord(b[0]) and int(a[1])<int(b[1]): #LU #L OR U
        while a[0]!=b[0] and int(a[1])!=int(b[1]):
            a = lu(a[0],int(a[1]))
            moves.append('LU')
            c+=1
            if a==b:
                print(c)
                for m in moves:
                    print(m)
                over = True
                break
        else:
            if not over:
                while int(a[1])==int(b[1]):
                    a =l(a[0],int(a[1]))
                    moves.append('L')
                    c+=1
                    if a==b:
                        print(c)
                        for m in moves:
                            print(m)
                        over = True
                        break
                while a[0]==b[0]:
                    a = u(a[0],int(a[1]))
                    moves.append('U')
                    c+=1
                    if a==b:
                        print(c)
                        for m in moves:
                            print(m)
                        over = True
                        break
