int diagonalDifference(vector<vector<int>> arr) {
int left_result = 0;
int right_result = 0;
int diagonalDiff = 0; 
for (int i = 0; i < arr.size(); i++){
     
  left_result += arr[i][i];
  right_result += arr[i][arr.size()-i-1];
}

diagonalDiff = left_result - right_result;
return abs(diagonalDiff);
}