//claculate the minimum height of binary tree
const minHeightTree =(root)=>{
if (!root) return 0;
let left = minHeightTree(root.left);
console.log(left)
let right = minHeightTree(root.right);
console.log(right)
if(left< right){
return left +1 ;
}else {
return right+1 ;
}
};