/in/foo.cc: In member function 'bool st::operator<(const st&) const':
/in/foo.cc:10:42: warning: self-comparison always evaluates to true [-Wtautological-compare]
   10 |         return chinese>b.chinese||chinese==chinese&&math>b.math;
      |                                   ~~~~~~~^~~~~~~~~
/in/foo.cc:10:51: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   10 |         return chinese>b.chinese||chinese==chinese&&math>b.math;
      |                                   ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~