foo.c: In function 'main':
foo.c:7:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n1,&n2);
  ^~~~~~~~~~~~~~~~~~~~~
foo.c:10:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a[i]);
   ^~~~~~~~~~~~~~~~~
foo.c:12:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&b[i]);
   ^~~~~~~~~~~~~~~~~
foo.c: In function 'FindSecondMax':
foo.c:19:6: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int x;
      ^

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