//User function Template for C++

/*

struct Node {

int key;

Node *left, *right;

};

*/

class Solution{

    public:

    // int moves = 0;

    // int solve(Node* root){

    //     if(root==NULL) return 0;

    //     int left = solve(root->left);

    //     int right = solve(root->right);

    //     int k =  left + right;

    //     int reqMove = root->key + k - 1; 

    //     moves+= abs(reqMove);

    //     return reqMove;

    // }

    // int distributeCandy(Node* root){

    //     if(root==NULL) return 0;

    //     int n = solve(root);

    //     return moves;

    // }

     int solve(Node* root, int &moves){

        if(root == NULL)

        {

            return 0;

        }

        int left = solve(root -> left, moves);

        int right = solve(root -> right, moves);

        moves = moves + abs(left) + abs(right);

        return root->key  -1 + left + right;

    }

    int distributeCandy(Node* root) {

        int moves = 0;

        solve(root, moves);

        return moves;

    }

};