#include <bits/stdc++.h>
using namespace std;

typedef long long LL;

int main() {
    int a, b;
    cin >> a >> b;

    LL res = 1;
    while (a > 1 && b--) {
        res *= a;
        if (res > 1e9) {
            res = -1;
            break;
        }
    }

    cout << res << endl;
    return 0;
}