#include <stdio.h>   
  
long v[14][3];   
  
long BS2(long x)   
{   
    int lo, hi, mid, last = 0;   
  
    for (lo = 1, hi = 12; lo <= hi; )   
    {   
    mid = lo + (hi-lo) / 2;   
    if (v[mid][2] <= x) last = mid, lo = mid+1;   
    else hi = mid-1;   
    }   
    return last;   
}   
  
int main()   
{   
 freopen("fact.in","r",stdin);   
 freopen("fact.out","w",stdout);   
 long p,n=0,i,x;   
 v[1][1]=25;   
 v[1][2]=6;   
 for (i=2;i<13;i++) {v[i][1]=v[i-1][1]*5;v[i][2]=v[i-1][1]+v[i-1][2];};   
 scanf("%ld",&p);   

 x=BS2(p);
 if (p!=0)
 {
 if (p>6)
 {
  if ((p<v[x+1][2])&&(p>v[x+1][2]-x-2)) {n=-1;p=0;};
  do
  {
   x=BS2(p);
   n=n+v[x][1];
   p=p-v[x][2];
  }
  while (p>5);
 }
 if (p==5) n=-1;
 else n=n+5*p;
 }
 else n=0;

 printf("%ld",n);
 return 0;
}