#!/usr/bin/env python
#coding:utf8

import sys
sys.setrecursionlimit(80000)

def read():
    text = sys.stdin.read().strip()
    elem = text.split()
    N = int(elem[0])
    M = int(elem[1])
    return N, M


def mypow(n, p):
    if p == 0:
        return 1

    t = mypow(n, p / 2)

    return t * t * n % 10 if p % 2 == 1 else t * t % 10
    

def work((N, M)):
    if not (1 <= N <= 10**10000 and 0 <= M <= 10**10000):
        print "??"
        return
    
    N %= 10
    print mypow(N, M)
    

if __name__ == "__main__":
    work(read())