class Stack:

def __init__(self):

self.stack = []

def push(self, element):

self.stack.append(element)

def top(self):

return self.stack[-1] if len(self.stack) != 0 else None

def pop(self):

return self.stack.pop()

class minimum_element_in_stack_with_extra_space:

def __init__(self):

self.s = Stack()

self.ss = Stack()

def push(self, element):

self.s.push(element)

if self.ss.top() is None or self.ss.top() >= element:

self.ss.push(element)

def pop(self):

if self.s.top() is None:

return -1

ans = self.s.top()

self.s.pop()

if self.ss.top() == ans:

self.ss.pop()

return ans

def get_min(self):

if self.ss.top() is None:

return -1

return self.ss.pop()

def main():

min_element = minimum_element_in_stack_with_extra_space()

min_element.push(5)

min_element.push(1)

min_element.push(0)

min_element.push(6)

print(min_element.get_min())

min_element.pop()

min_element.pop()

print(min_element.get_min())

if __name__ == "__main__":

main()