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

int f(int p){
int x=5;
int z=1;
int y;
while (z!=p){
    x=x+5;
    y=x;
    while (y){
        if (y%5==0){
            z++;
            y=y/5;
        }
        else y=0;
    }
}
return x;
}

int main()
{
ifstream in("fact.in");
ofstream out("fact.out");
int p;
in>>p;
out<<f(p);
}