#include <iostream>
#include <algorithm>
#include <cmath>
#include <fstream>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");
int main(){
    int p;
    long long x=0;
    in>>p;
    if(p==0){
        out<<1;
        return 0;
    }
    int nr=0,x2;
    while(p>0){
        x+=5;
        x2=x;
        while(x2%5==0)
            --p , x2/=5;
    }
    if(p!=0)
        out<<-1;
    else
        out<<x;
    return 0;
}