#include <bits/stdc++.h>
#define ll long long
ll p,i,m,s=0;
using namespace std;
int gcd(int a,int b){
    if(b==0) return a;
    return gcd(b,a%b);
}
int main() {
    ifstream cin;
    cin.open("fact.in");
    ofstream cout;
    cout.open("fact.out");
    cin>>p;
    for(i=1;i<=100000000;i++){
        m=i;
        while(m%5==0){
            s++;
            m=m/5;
        }
        if(s==p){
            cout<<i;
            return 0;
        }
        else if(s>p)
        {
            cout<<"-1";
            return 0;
        }

    }

    return 0;
}