#include <iostream>
using namespace std;
int main()
{
    long long  int AC,WA,TLE;
    cin>>AC>>WA;
    TLE=AC;
    for(long long i=1;i<=WA;i++)
    {
        AC=AC*TLE;
    }
    if(AC>=1000000000)
        cout<<"-1";
    else
        cout<<AC;
    return 0;
}