foo.c: In function 'main':
foo.c:43:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &R, &C);
     ^~~~~~~~~~~~~~~~~~~~~~
foo.c:46:13: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d", &a[i][j]);
             ^~~~~~~~~~~~~~~~~~~~~

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