#include <iostream>
using namespace std;
int main(){
     int n, numar=0, produs=1, p;
     cout<<"Introduceti un numar:";
     cin>>p;
     for(int i=1;i<=n;i++){
         produs*=n;
     }
     for(;;){
         if(produs%10==0){
             numar+=1;
             produs/=10;
         }
         else{
             break;
         }
         if(produs/10<1){
             break;
         }
     }
     if(numar==p){
         cout<<n<<"\n\n";
     }
     else{
         cout<<"-1"<<"\n\n";
     }
     return 0;
}