foo.c: In function 'isprime':
foo.c:9:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
    9 |  for(int i=2; i<=sqrt(x); i++)
      |  ^~~
foo.c:12:3: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   12 |   return 1;
      |   ^~~~~~
foo.c: In function 'main':
foo.c:28:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   28 |  scanf("%d%d", &n1, &n2);
      |  ^~~~~~~~~~~~~~~~~~~~~~~
foo.c:30:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   30 |   scanf("%d", &a[i]);
      |   ^~~~~~~~~~~~~~~~~~
foo.c:32:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   32 |   scanf("%d", &b[j]);
      |   ^~~~~~~~~~~~~~~~~~

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