foo.c: In function 'main':
foo.c:38:29: warning: implicit declaration of function 'abs' [-Wimplicit-function-declaration]
   38 |                 sum = sum + abs(a[i] - X) + abs(b[i] - Y);
      |                             ^~~
foo.c:3:1: note: include '<stdlib.h>' or provide a declaration of 'abs'
    2 | #include<math.h>
  +++ |+#include <stdlib.h>
    3 | int main()

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