foo.c: In function 'main':
foo.c:19:18: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   19 |    if (year%4==0 && year%100!=0 || year%400==0)
      |        ~~~~~~~~~~^~~~~~~~~~~~~~
foo.c:5:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    5 |  scanf("%d %d",&year,&month);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~

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