foo.cc: In function 'int main()':
foo.cc:39:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   39 |         for(int i=1;i<=n;i++) scanf("%lf %lf",&a[i].x,&a[i].y),tmp[i]=a[i];
      |                               ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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