#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
const int N = 1e9;
long long qmi(long long a,long long b)
{
    if(a >= 10 && b >= 10) return -1;
    long long res = 1;
    while(b){
        if(b&1) res = res*a;
        if(res > N) return -1;
        a = a*a;
        b >>= 1;
    }
    if(res > N) return -1;
    return res;
}
int main()
{
    long long a,b;
    cin>>a>>b;
    cout<<qmi(a,b)<<endl;
}