#include <iostream>
#include <stdio.h>
#include <fstream>
using namespace std;


int P,i,N,p,c,a;
int main()
{FILE  *f1,  *f2;
f1=fopen("fact.in","r");
    f2=fopen("fact.out","w");
    fscanf(f1,"%d", &P);
p=1;
if(P=0)
     fprintf(f2,"%d", 1);
    else
{for(i=1;i<5*P;i++)
  {
      p=p*i;
  }

}

while(p!=0)
{ c=p%10;
  p=p|10;
  if(c=0)
     {
         a++;
     }

}
if(a=P)
 {fprintf(f2,"%d",5*P);

 }
fclose(f1);fclose(f2);
return 0;
}