#include <iostream>
#include <fstream>

ifstream f("fact.in");
ofstream g("fact.out");

using namespace std;

int main()
{
    int i=2;
    int p,ct5=0,ct2=0;
    f>>p;
    if(p==0){
        g<<1;
        return 0;
    }
    while(min(ct5,ct2)!=p)
    {
        i++;
        if(i%5==0)
        {
            int copie=i;
            while(copie%5==0){
                ct5++;
                copie/=5;
            }
        }
        if(i%2==0)
        {
            int copie=i;
            while(copie%2==0)
            {
                ct2++;
                copie/=2;
            }
        }
    }
    g<<i;

    return 0;
}