from decimal import *
getcontext().prec = 1100000
N = Decimal(input())
M = Decimal(input())
x = N / M
s = str(x)
if(len(s)>100000):
    print(-1)
else:
    for i in range(len(s)):
        if s[i] == 'E':
            s = s[:i]
            break

    for i in reversed(range(len(s))):
        if s[i]!='0' and s[i]!='.':
            print(s[i])
            break