#include <iostream>
#include <fstream>
std::ifstream fin("fact.in");
std::ofstream fout("fact.out");
using namespace std;

int Nr5(unsigned long x)
{
    int cnt=0;
    while(x%5==0)
    {
        cnt++;
        x/=5;
    }
    return cnt;
}

int main()
{
    unsigned int N;
    unsigned long long x=0;
    fin >> N;
    if(N==0) {
        cout << 1;
        return 0;
    }
    for(unsigned int i=0;i<N;)
    {
        x += 5;
        i += Nr5(x);
    }
    fout << x;
    return 0;
}