answer.code: In function ‘long long int ask(long long int)’:
answer.code:34:37: error: expected ‘;’ before ‘long’
   34 |     cout<<"? "<<x<<endl;cout.flush()
      |                                     ^
      |                                     ;
answer.code:36:10: error: ‘z’ was not declared in this scope
   36 |     cin>>z;
      |          ^
answer.code: In function ‘void solve()’:
answer.code:56:49: error: expected ‘;’ before ‘return’
   56 |             cout<<"! "<<start<<endl;cout.flush()
      |                                                 ^
      |                                                 ;
   57 |             return;
      |             ~~~~~~                               
answer.code:81:25: error: expected ‘;’ before ‘return’
   81 |             cout.flush()
      |                         ^
      |                         ;
   82 |             return;
      |             ~~~~~~