foo.c: In function 'main':
foo.c:12:6: warning: implicit declaration of function 'ys' [-Wimplicit-function-declaration]
   12 |   yu=ys(fm,fz);
      |      ^~
foo.c:5:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    5 |  scanf("%d",&n);
      |  ^~~~~~~~~~~~~~
foo.c:7:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    7 |   scanf("%d%d",&a[i],&b[i]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~

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