You have number *a*, whose decimal representation quite luckily contains digits 1, 6, 8, 9. Rearrange the digits in its decimal representation so that the resulting number will be divisible by 7.

Number *a* doesn't contain any leading zeroes and contains digits 1, 6, 8, 9 (it also can contain another digits). The resulting number also mustn't contain any leading zeroes.
The first line contains positive integer *a* in the decimal record. It is guaranteed that the record of number *a* contains digits: 1, 6, 8, 9. Number *a* doesn't contain any leading zeroes. The decimal representation of number *a* contains at least 4 and at most 10<sup class="upper-index">6</sup> characters.
def main():
    a = input()
    l = len(a)
    book = [0] * 128
    a = list(a)
    for i in range (l):
        a[i] = chr(ord(a[i]) - ord('0'))
        book[ord(a[i])] += 1
    num = 0
    m = 0
    buf = []
    for i in range (1,10):
        if i in (1, 8, 6, 9):
            for j in range (1, book[i]):
                buf.append(i)
                m = (10 * m + i) % 7
                num += 1
        else:
            for j in range (1,book[i]+1):
                buf.append(i)
                m = (10 * m + i) % 7
                num += 1
    m = ( m * 10000 ) % 7
    mp = [9681, 1896,9861, 1698, 6891, 6981, 6819]
    buf.append(mp[m])
    num += 4
    buf.append('0' * (l - num))
    print(''.join(map(str, buf)))

main()

  	 		 					 		 			   	 	