#include <iostream>
#include <fstream>

using namespace std;

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

int main()
{
    int n, i, x, cx;
    f >> n;
    x = 0;
    for ( i = 0 ; i < n; i++) {
        x += 5;
        cx = x / 5;
        while ( cx % 5 == 0 ) {
            cx /= 5;
            i++;
        }
    }
    if ( x == 0 )
        g << "1";
    else
        g << x;
    return 0;
}