foo.c: In function 'main':
foo.c:12:13: warning: format '%ld' expects argument of type 'long int', but argument 2 has type 'double' [-Wformat=]
   printf("%ld\n", fibs(n)-pow(2,n-4)+1);
           ~~^     ~~~~~~~~~~~~~~~~~~~~
           %f
foo.c:8:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ^~~~~~~~~~~~~~~

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