10515.cpp

#include <bits/stdc++.h>

int main() {
    char a[101], b[101];
    int l2, j, l1, n, m;
    while (scanf("%s %s", a, b) == 2) {
        l1 = strlen(a);
        l2 = strlen(b);
        m = a[l1 - 1] - 48;
        n = 0;
        if (strcmp(a, "0") == 0 && strcmp(b, "0") == 0) {
            return 0;
        } else if (strcmp(b, "0") == 0) {
            printf("1\n");
        } else {
            if (m == 0) {
                printf("0\n");
            } else {
                if (l2 >= 2)
                    n = (10 * (b[l2 - 2] - 48)) + (b[l2 - 1] - 48);
                else
                    n = b[l2 - 1] - 48;
                if (n == 0) {
                    n = 4;
                }
                for (j = m; n > 1; n--) {
                    j = (j * m);
                    j = j % 10;
                }
                printf("%d\n", j);
            }
        }
    }
    return 0;
}