foo.cc: In function 'int main()':
foo.cc:26:12: warning: unused variable 'x' [-Wunused-variable]
   26 |     ll a,b,x,y;
      |            ^
foo.cc:26:14: warning: unused variable 'y' [-Wunused-variable]
   26 |     ll a,b,x,y;
      |              ^
foo.cc:31:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   31 |         scanf("%lld%lld",&a,&b);
      |         ~~~~~^~~~~~~~~~~~~~~~~~

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