#include <bits/stdc++.h>
using namespace std;

// Definition for binary tree
struct TreeNode {
     int val;
     TreeNode *left;
     TreeNode *right;
     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};


void changeData(TreeNode* root){
    root -> val = 20;
}

int lca(TreeNode* A) {
    A -> val = 10;
    cout<<A->val<<endl;

    changeData(A);
    cout<<A->val<<endl;
}

int main() {
    // your code goes here
    lca(new TreeNode(5));
    return 0;
}