#include <fstream>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");
int p,i=1,f=1,k=1,j,o;
int main()
{
        in>>p;
        for(o=1; o<=p; o++)
            k=k*10;
        while(f%k!=0)
        {
            f=f*i;
            i++;
        }
        if(p==2)
            out<<i-1<<endl;
        else
            out<<i<<endl;
    return 0;
}