View Compilation Error

0_0_21358212_6314.cpp: In function 'int solve(std::pair<int, int>, std::pair<int, int>)':
0_0_21358212_6314.cpp:19:3: error: 'ans' was not declared in this scope
   ans++;
   ^
0_0_21358212_6314.cpp:21:3: error: 'ans' was not declared in this scope
   ans++;
   ^
0_0_21358212_6314.cpp:22:9: error: 'ans' was not declared in this scope
  return ans;
         ^