foo.cc: In function 'int main()':
foo.cc:52:9: warning: unused variable 'top1' [-Wunused-variable]
   52 |     int top1=0,top2=1;
      |         ^~~~
foo.cc:52:16: warning: unused variable 'top2' [-Wunused-variable]
   52 |     int top1=0,top2=1;
      |                ^~~~

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