foo.cc: In function 'int main()':
foo.cc:19:6: warning: unused variable 'a' [-Wunused-variable]
   19 |  int a,b;
      |      ^
foo.cc:19:8: warning: unused variable 'b' [-Wunused-variable]
   19 |  int a,b;
      |        ^
foo.cc:29:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   29 |   scanf("%d %d",&pos[i].first,&pos[i].second);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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