#include <iostream>
#include <fstream>
using namespace std;

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

int main()
{
    unsigned long long p, n;
    int i;
    fin>>p;
    if(p==0) fout<<1;
    else{
        for(i=5; p > 1; i=i+5){
            n = i;
            while(n%5==0){
                --p;
                n = n/5;
            }
        }

    }
    fout<<i;

}