#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll a,b,ans;
int main(){
	freopen("csp2022pj_pow.in","r",stdin);
	freopen("csp2022pj_pow.out","w",stdout);
	cin>>a>>b;
	if(b==1){
		if(a<=1000000000){cout<<a;return 0;}
		else{cout<<-1;return 0;}
	}
	else if(b==2){
		if(a*a<=1000000000){cout<<a;return 0;}
		else{cout<<-1;return 0;}
	}
	ans=a;
	if(a>10&&b>9){cout<<-1;return 0;}
	else{
		for(ll i=1;i<b;i++){
			if(ans*a>1000000000){
				cout<<-1;
				return 0;
			}
			ans*=a;
		}
		cout<<ans;
	}
	return 0;
}