#include <iostream>
#include <fstream>

using namespace std;

ifstream fi("fact.in");
ofstream fo("fact.out");

int main()
{
    int a,i,d,c,n,k;
    bool gasit=false;

    fi>>n;

    i=1;
    d=0;
    c=0;

    while(!gasit)
    {
        a=i;
        while(a%2==0)
        {
            d++;
            a/=2;
        }

        while(a%5==0)
        {
            c++;
            a/=5;
        }

        if((d==n && d<=c) || (c==n && c<=d))
            gasit=true;
        i++;
    }

    fo<<i-1;

    return 0;
}