# write your code here
class StackOverflowError(Exception):
    def __init__(self):
        pass
    
    def __str__(self):
        return 'StackOverflowError: The stack is full'
    
class StackEmptyError(Exception):
    def __init__(self):
        pass
    
    def __str__(self):
        return 'StackEmptyError: The stack is empty'
    
class Stack:
    def __init__(self, n):
        self.n = n
        self.a = [] 
        
    def push(self, item):
        if len(self.a) == self.n:
            raise StackOverflowError()
        self.a.append(item)
    
    def pop(self):
        if len(self.a) == 0:
            raise StackEmptyError()
        f = self.a[-1]
        del self.a[-1]
        return f
    
    def peek(self):
        if len(self.a) == 0:
            raise StackEmptyError()
        return self.a[-1]
        
# FROZEN_SECTION_START
if __name__ == '__main__':
    for command in input().split(';'):
        command = command.strip()
        try:
            exec(command)
        except Exception as e:
            print(e)