#include <fstream>

using namespace std;

int main()
{
    int n, i;
    ifstream in("fact.in");
    ofstream out("fact.out");
    in>>n;
    for(i=5;n>0;i+=5){
        while(i%5==0){
            i/=5;
            --n;
        }
    }
    out<<i;
    return 0;
}