#include <iostream>
#include <fstream>
#include <stdio.h>
using namespace std;
int p=0,i,P,c,a;
#define N 1000000000
int main()
{fstream f("fact.in",ios::in);
fstream g("fact.out",ios::out);
f>>P;
for(i=1;i<=N;i++)
{p=P*i;
while(p)
{c=p%10;
p=p/10;
if (c=0)
 a++;
}

g<<N;}
g.close();f.close();

    return 0;
}