foo.c: In function 'main':
foo.c:5:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    5 |  scanf("%d%d", &m, &n);
      |  ^~~~~~~~~~~~~~~~~~~~~
foo.c:9:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    9 |    scanf("%d", &a[i][j]);
      |    ^~~~~~~~~~~~~~~~~~~~~

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