foo.c: In function 'main':
foo.c:6:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ^~~~~~~~~~~~~~~
foo.c:7:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &x1);
     ^~~~~~~~~~~~~~~~
foo.c:10:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &x);
         ^~~~~~~~~~~~~~~

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