#include <iostream>
#include <fstream>

using namespace std;

int main()
{
    ifstream f("fact.in");
    ofstream g("fact.out");
    int p,m=0,k=0,s=0,x=0,cx;
    f >> p;
    for(int i=1;i<=10000000;++i)
    {
        x+=5;
        cx=x;
        m=0;
        k=cx;
        while(cx%5==0)
        {
            cx=cx/5;
            ++m;
        }
        s=s+m;
        if(s==p)
        {
            break;
        }
    }
    g << k;

    return 0;
}