View Compilation Error

0_0_21089608_30000.cpp:81:1: error: 'Ans' does not name a type
 Ans query(int x)
 ^
0_0_21089608_30000.cpp: In function 'void work(int, int)':
0_0_21089608_30000.cpp:116:3: error: 'Ans' was not declared in this scope
   Ans sum=query(tr[j].c);
   ^
0_0_21089608_30000.cpp:117:3: error: 'sum' was not declared in this scope
   sum.len++;
   ^