Question $23$

When we have two tree walks, they generate a unique tree. Suppose we traversed a tree $T$

for an in$-$order tree walk and pre$-$order tree walk as follows;

In order tree walk of tree $T=\{15,28,35,38,40,45,55,60\}$

Pre order tree walk of tree $T=\{55,28,15,35,45,38,40,60\}$

What is the height of the tree $T?$