class Tree:
    def __init__(self, n):
        self.root = n           # POCETNI BROJ
        self.left  = None
        self.right = None

    def __repr__(self):
        ja = str(self.root) + '|'
        if self.left:
            ja += self.left.__repr__()
        if self.right:
            ja += self.right.__repr__()
        ja += '||'
        return ja

    def dfs(self, n):
        if self.root == n:
            exit(f'nasao sam {n}')
        if self.left:
            self.left.dfs(n)
        if self.right:
            self.right.dfs(n)

    def add(self, n):
        if n == self.root:
            return
        if n < self.root and self.left == None:
            self.left = Tree(n)
        elif n > self.root and self.right == None:
            self.right = Tree(n)
        elif n < self.root:
            self.left.add(n)
        else:
            self.right.add(n)

tree = Tree(12)
tree.add(3)
tree.add(14)
tree.add(2)
tree.add(5)
tree.add(13)
tree.add(17)
tree.add(1)
tree.add(20)
tree.add(22)

tree.dfs(5)