/in/foo.cc: In function 'int main()':
/in/foo.cc:7:33: warning: left operand of comma operator is a reference, not call, to function 'std::ios_base::sync_with_stdio' [-Waddress]
  ios::sync_with_stdio, cin.tie(0), cout.tie(0);
                                 ^
/in/foo.cc:7:33: warning: left operand of comma operator has no effect [-Wunused-value]