#include<bits/stdc++.h>
using namespace std;
int main(){
	long long s=1;
	int a,b;
	cin>>a>>b;
	if(a>10&&b>10) cout<<-1;
	else{
		for(int i=0;i<b;i++){
		s*=a;
	}
	if(s>1000000000) cout<<-1;
	else cout<<s;
	}
return 0;}

/**************************************************************
	Problem: 2405
	User: fzy001
	Language: C++
	Result: Accepted
	Time:1007 ms
	Memory:2072 kb
****************************************************************/