#include <iostream>
#include <fstream>
using namespace std;
int main()
{
     long int p;
ifstream f("fact.in");
ofstream g("fact.out");

int i;
f>>p;
if(p==0){g<<1;return;}

long p5[12],nrz[12];
int cap[12];
p5[0]=1;


for(i=1;i<=11;i++)
{p5[i]=p5[i-1]*5;cap[i]=4;}
  nrz[1]=1;
for(i=2;i<=11;i++)
  nrz[i]=p5[i-1]+nrz[i-1];
i=11;

long n=0;
while(i>0&&p)
 { while(p>=nrz[i]&&cap[i])
	  {n+=p5[i];cap[i]--;p-=nrz[i];}
  i--;
 }

if(i==0&&p)n=-1;


g<<n;
}