#include<stdio.h>

int main()
{
  FILE *f=fopen("fact.in", "r");
  FILE *g=fopen("fact.out", "w");
  while(!feof(f))
  {
    long p,i,j,s;
    fscanf(f, "%d", &p);
    i=5;
    s=0;
    while(s!=p)
    {
      if(s>p)
      {
      fprintf(g, "%d", -1);
      goto end;
      }
      if(i%5==0)
      {
      j=i;
      while(j%5==0)
	{
	s++;
	j=j/5;
	}
      }
      i=i+5;
    }
    fprintf(g, "%d", i-5);
  }
  end:
  fclose(g);
  return 0;
}