#include<bits/stdc++.h>
using namespace std;
ifstream fin("factorial.in");
ofstream fout("factorial.out");
int n;
int factorial(int n)
{
    int p=0,i=0,ii;
    if(n==0)
        return 1;
    else
        while(p<n)
        {
            i+=5;
            ii=i;
            while(ii%5==0)
            {
                ii/=5;
                p++;
            }
        }
    return i;
}
int main()
{
    fin>>n;
    fout<<factorial(n);
    return 0;
}