class Node:

def __init__(self, data):

self.data=data

self.left=None

self.right=None

def findSecondMinimumValue( root):

if root is None:

return -1

if root.left == None and root.right == None:

return -1

left = root.left.data

right = root.right.data

if root.data == root.left.data:

left = findSecondMinimumValue(root.left)

if root.data == root.right.data:

right = findSecondMinimumValue(root.right)

if left != -1 and right != -1:

return min(left, right)

elif left != -1:

return left

else:

return right

root = Node(2)

root.left = Node(3)

root.right = Node(2)

root.right.left = Node(8)

root.right.right = Node(2)

root.left.left = Node(3)

root.left.right = Node(6)

root.left.left.left = Node(3)

root.left.left.right = Node(5)

root.left.right.left = Node(6)

root.left.right.right = Node(7)

root.right.left.left = Node(20)

root.right.left.right = Node(8)

root.right.right.right = Node(9)

root.right.right.left = Node(2)

print(findSecondMinimumValue( root))