foo.cc: In function 'int main()':
foo.cc:24:4: warning: this 'else' clause does not guard... [-Wmisleading-indentation]
    else cout<<"NO";return 0;
    ^~~~
foo.cc:24:20: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'else'
    else cout<<"NO";return 0;
                    ^~~~~~

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