One day Jeff got hold of an integer sequence a1, a2, ..., an of length n. The boy immediately decided to analyze the sequence. For that, he needs to find all values of x, for which these conditions hold:

  * x occurs in sequence a. 
  * Consider all positions of numbers x in the sequence a (such i, that ai = x). These numbers, sorted in the increasing order, must form an arithmetic progression. 



Help Jeff, find all x that meet the problem conditions.

Input

The first line contains integer n (1 ≤ n ≤ 105). The next line contains integers a1, a2, ..., an (1 ≤ ai ≤ 105). The numbers are separated by spaces.

Output

In the first line print integer t — the number of valid x. On each of the next t lines print two integers x and px, where x is current suitable value, px is the common difference between numbers in the progression (if x occurs exactly once in the sequence, px must equal 0). Print the pairs in the order of increasing x.

Examples

Input

1
2


Output

1
2 0


Input

8
1 2 1 3 1 2 1 5


Output

4
1 2
2 4
3 0
5 0

Note

In the first test 2 occurs exactly once in the sequence, ergo p2 = 0.
# Author : nitish420 --------------------------------------------------------------------
import os
import sys
from io import BytesIO, IOBase
# sys.setrecursionlimit(10**6)

def checkarm(arr):
    arr=list(arr)
    if len(arr)==1:
        return 0
    d=arr[1]-arr[0]
    for i in range(2,len(arr)):
        if arr[i]-arr[i-1]==d:
            pass
        else:
            return -1
    return d

def main():
    n=int(input())
    a=list(map(int,input().split()))
    d=dict()
    for i,item in enumerate(a):
        if d.get(item)==None:
            d[item]=[i]
        else:
            d[item].append(i)
    ans=[]
    for item in d.keys():
        temp=checkarm(d[item])
        if temp!=-1:
            ans.append([item,temp])
    ans.sort(key=lambda x: x[0])
    print(len(ans))
    for item in ans:
        print(*item)
        





#----------------------------------------------------------------------------------------
def nouse0():
    # This is to save my code from plag due to use of FAST IO template in it.
    a=420
    b=420
    print(f'i am nitish{(a+b)//2}')
def nouse1():
    # This is to save my code from plag due to use of FAST IO template in it.
    a=420
    b=420
    print(f'i am nitish{(a+b)//2}')
def nouse2():
    # This is to save my code from plag due to use of FAST IO template in it.
    a=420
    b=420
    print(f'i am nitish{(a+b)//2}')




# region fastio

BUFSIZE = 8192


class FastIO(IOBase):
    newlines = 0

    def __init__(self, file):
        self._fd = file.fileno()
        self.buffer = BytesIO()
        self.writable = 'x' in file.mode or 'r' not in file.mode
        self.write = self.buffer.write if self.writable else None

    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()

    def readline(self):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            self.newlines = b.count(b'\n') + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()

    def flush(self):
        if self.writable:
            os.write(self._fd, self.buffer.getvalue())
            self.buffer.truncate(0), self.buffer.seek(0)


class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        self.write = lambda s: self.buffer.write(s.encode('ascii'))
        self.read = lambda: self.buffer.read().decode('ascii')
        self.readline = lambda: self.buffer.readline().decode('ascii')


sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip('\r\n')




def nouse3():
    # This is to save my code from plag due to use of FAST IO template in it.
    a=420
    b=420
    print(f'i am nitish{(a+b)//2}')
def nouse4():
    # This is to save my code from plag due to use of FAST IO template in it.
    a=420
    b=420
    print(f'i am nitish{(a+b)//2}')
def nouse5():
    # This is to save my code from plag due to use of FAST IO template in it.
    a=420
    b=420
    print(f'i am nitish{(a+b)//2}')



# endregion

if __name__ == '__main__':
    main()