foo.c: In function 'main':
foo.c:5:10: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'long long int *' [-Wformat=]
  scanf("%d",&n);
         ~^  ~~
         %lld
foo.c:7:11: warning: format '%d' expects argument of type 'int', but argument 2 has type 'long long int' [-Wformat=]
  printf("%d\n",s);
          ~^
          %lld
foo.c:5:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ^~~~~~~~~~~~~~