class Node:
    def __init__(self, data=None, left=None, right=None):
        self.data = data
        self.left = left
        self.right = right
        self.size = 1


class BinarySearchTree:
    def __init__(self):
        self.root = None





    def insert(self, val):

        if self.root ==None:
            self.root = Node(val)
        else:
            current = self.root
            size1 =2
            while 1:

                if current.data > val:
                    if current.left == None:
                        current.left = Node(val)
                        if self.root.size < size1:
                            self.root.size = size1
                        break
                    else:
                        current = current.left

                elif current.data < val:
                    if current.right == None:
                        current.right = Node(val)

                        if self.root.size < size1:
                            self.root.size = size1
                        break

                    else:
                        current = current.right

                else:
                    break

                size1 +=1


tree = BinarySearchTree()

for i in list(map(int,input().split())):
    if i != 0:
        tree.insert(i)

print(tree.root.size)