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

int main()
{
    int p,x;
    ifstream f("fact.in");
    ofstream g("fact.out");
    f>>p;
    int n=0,s=0;
    if(p==0) g<<"1";
    else
    {
        while(s<p)
        {
          n+=5;
          x=n;
          while(x%5==0)
         {
            s++;
            x/=5;
         }
        }
       g<<n;
    }


}