/* p6.c */

#include <stdio.h>

int main()
{
   FILE *f1;
   FILE *f2;
   int x;

   f1 = fopen("in.txt", "r");
   if (f1 == 0)
   {
      perror("f1 failure:");
      exit(1);
   }

   f2 = fopen("out.txt", "w");
   if (f2 == 0)
   {
      perror("f2 failure:");
      exit(2);
   }

   if (fscanf(f1, "%d", &x) != 1)
   {
      perror("scanf failure:");
      exit(2);
   }
   fprintf(f2, "%d\n", x);

}