foo.c: In function 'main':
foo.c:8:2: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
  scanf("%d %d",&n,&k);
  ^~~~~
foo.c:8:2: warning: incompatible implicit declaration of built-in function 'scanf'
foo.c:8:2: note: include '<stdio.h>' or provide a declaration of 'scanf'
foo.c:8:10: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'long long int *' [-Wformat=]
  scanf("%d %d",&n,&k);
         ~^     ~~
         %lld
foo.c:8:13: warning: format '%d' expects argument of type 'int *', but argument 3 has type 'long long int *' [-Wformat=]
  scanf("%d %d",&n,&k);
            ~^     ~~
            %lld
foo.c:10:11: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'long long int *' [-Wformat=]
   scanf("%d",&a[i]);
          ~^  ~~~~~
          %lld
foo.c:29:2: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
  printf("%d",count);
  ^~~~~~
foo.c:29:2: warning: incompatible implicit declaration of built-in function 'printf'
foo.c:29:2: note: include '<stdio.h>' or provide a declaration of 'printf'
foo.c:29:11: warning: format '%d' expects argument of type 'int', but argument 2 has type 'long long int' [-Wformat=]
  printf("%d",count);
          ~^
          %lld