#include <bits/stdc++.h>
using namespace std;

ifstream in("fact.in");
ofstream out("fact.out");

int number_of_zeros(int nr){
    int rez = 0;
    for(int i = 5; i <= nr ; i *= 5){
        rez += nr / i;
    }

    return rez;
}

int main(){
    int n, fact;

    in >> n;

    if (n == 0){
        out << 1 << "\n";
        return 0;
    }

    if (n == 1){
        out << "10\n";
        return 0;
    }
    
    
    for (int i = 2; ; i++){
        int temp = number_of_zeros(i);
        if (temp == n){
            out << i << "\n";
            return 0;
        }

        if (temp > n){
            out << "-1\n";
            return 0;
        }
    }
}