//Factorial
#include <bits/stdc++.h>
using namespace std;

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

int main()
{
    long long xx,p,nr,x;
    fin>>p;
    if(p==0)
    {
        fout<<"1";
        return 0;
    }
    x=5;
    nr=0;
    while(nr<p)
    {
        xx=x;
        while(xx%5==0)
        {
            nr++;
            xx=xx/5;
        }
        x=x+5;
    }
    x=x-5;
    fout<<x;

	return 0;
}