#include<stdio.h>
void main ()
{
  long p;
  int i,v[10],pr[10000],k,t,i2;
  FILE*f=fopen("factorial.in","r");
  FILE*g=fopen("factorial.out","w");
  fscanf(f,"%ld",&p);
  i=1;
  while (p!=0)
   { v[i++]=p%10;
     p=p/10;}
  k=1;
  t=0;
  for (i2=1;i2<=i;i2++)
    { pr[k++]=(v[i]*5+t)%10;
      t=(v[i]*5+t)/10;}
  if (t!=0) pr[k]=t;
   else k--;
  for (i=k;i>=1;i++) fprintf(g,"%d",pr[i]);
					  }