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

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int a, b;
	cin >> a >> b;
	if (a == 1) cout << 1 << endl;
	else if (b == 1) cout << a << endl;
	else if (b >= 27) cout << -1 << endl;
	else if (a >= 31623) cout << -1 << endl;
	else{
		ll c = 1;
		while(b > 0)
		{
			b --;
			if (1e9 / (double)(c) < a && b != 0)
			{
				cout << -1 << endl;
				return 0;
			}
			c *= a;
		}
		cout << c << endl;
	}
	return 0;
}