#include <fstream>
#include <iostream>
using namespace std;
long p;
ifstream f("fact.in");
ofstream g("fact.out");
long long factorial(long long s,long long t)
{
    if (s>t) return 1;
    long long m = (s+t)/2;
    return factorial(s,m-1)*factorial(m+1,t)*m;
}
int nrcif(long long x)
{
    if (x%10 == 0) return nrcif(x/10)+1;
    else return 0;
}
int main()
{
    f>>p;
    f.close();
    int i=p;
    cout<<factorial(1,45);
    while (i<32000)
    {
        if (nrcif(factorial(1,i)) == p) {g<<i; break;}
        i++;
    }
    g.close();
}