View Compilation Error

0_0_38771793_22373.cpp: In function 'void solve()':
0_0_38771793_22373.cpp:16:28: error: 'a' was not declared in this scope
   16 |                         mp[a[i]] ++;
      |                            ^
0_0_38771793_22373.cpp:19:32: error: 'a' was not declared in this scope
   19 |                         if (mp[a[i]] % 2 == 1 && mp[a[i] + 1] % 2 == 1 && mp[a[i] + 2] != 0) {
      |                                ^
0_0_38771793_22373.cpp:25:35: error: 'a' was not declared in this scope
   25 |                         ans += mp[a[i]] / 2;
      |                                   ^