#include <bits/stdc++.h>
using namespace std;
 
int main() {
	// your code goes here
	int n=3 , m=20;
	int start=0 , end =m , kok;
    int mid;
    while(start<end){
        mid=(start+end)/2;
        kok=pow(mid,n);
        cout<<"power "<<pow(mid,n)<<"  mid "<<mid<<"  start "<<start<<"   end "<<end<<endl;
        if(kok==m){
             cout<<mid<<endl;
             break;
 
        }else if(kok>m){
            end=mid-1;
        }
        else if(kok<m){
            start=mid+1;
        }
    }
   cout<<"-1"<<endl;
	return 0;
}

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