class Node:
    def __init__(self, x):
        self.key = x
        self.left = None
        self.right = None


def insert(tree, x):
    if tree is None:
        return Node(x)
    if x < tree.key:
        tree.left = insert(tree.left, x)
    elif x > tree.key:
        tree.right = insert(tree.right, x)
    return tree


def height(tree):
    if tree is None:
        return 0
    return max(height(tree.left), height(tree.right)) + 1


def go(tree):
    if tree is None:
        return
    go(tree.left)
    print(tree.key, end=' ')
    go(tree.right)


def traverse(tree):
    go(tree)
    print()


a = list(map(int, input().split()))[:-1]
tree = None
for i in a:
    tree = insert(tree, i)
# traverse(tree)
print(height(tree))