#include <fstream>

using namespace std;

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

int nrdivp(int x){
    int n = 0, idk = 5;
    while(idk <= n){
        n += n / idk;
        idk *= 5;
    }

    return n;
}

int main()
{
    int n;
    fin >> n;

    int rez;

    for(int p = (1<<30); p > 1; p>>=1){
        int lol = nrdivp(p);
        if(lol <= n){
            rez += p;
        }
    }
    if(v[poz] != x) rez = -1;

    fout << rez;
}