#include <bits/stdc++.h>
using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");
int n,p,ok;
bool fact=1;
int main()
{
    fin>>p;
    n=p;
    for (int i=1;i<=n;i++)
    {
        fact=fact*i;
    }
     while (fact%10==0)
     {
         ok++;
         fact=fact/10;
     }
     fout<<n+1;
}