#include<bits/stdc++.h>
using namespace std;
int main()
{
	int  a,b;
	cin>>a>>b;
	long long sum=1;
	for(int i=1;i<=b;i++)
	{
		sum*=a;
	}
	if(sum>1000000000) cout<<"-1"<<endl;
	else cout<<sum<<endl;
	return 0;
}