foo.cc: In function 'int main()':
foo.cc:12:28: warning: unused variable 'ci' [-Wunused-variable]
   12 |     int n,i,left,right,mid,ci,m,last=1,haha=0,ans;
      |                            ^~
foo.cc:12:33: warning: unused variable 'last' [-Wunused-variable]
   12 |     int n,i,left,right,mid,ci,m,last=1,haha=0,ans;
      |                                 ^~~~
foo.cc:77:10: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
   77 |    cout<<ans;
      |          ^~~

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