foo.cc: In function 'int main()':
foo.cc:31:2: warning: this 'else' clause does not guard... [-Wmisleading-indentation]
  else cout<<"YES";return 0;
  ^~~~
foo.cc:31:19: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'else'
  else cout<<"YES";return 0;
                   ^~~~~~

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。