answer.code: In function ‘int main()’:
answer.code:66:21: error: redeclaration of ‘int i’
   66 |                 int i = 1, r = i - 1;
      |                     ^
answer.code:48:17: note: ‘int i’ previously declared here
   48 |         for(int i = 2; i <= n; i++)
      |                 ^
answer.code:67:23: error: ‘l’ was not declared in this scope
   67 |                 while(l < r)
      |                       ^
answer.code:74:26: error: ‘l’ was not declared in this scope
   74 |                 if(check(l, i))
      |                          ^