Maximum Element

stack = []
M = []

for _ in range(int(input())):
    d = [int(x) for x in input().split()]
    if d[0] == 1:
        stack.append(d[1])
        M.append(max(d[1], M[-1]) 
                 if M else d[1])
    elif d[0] == 2:
        stack.pop()
        M.pop()
    elif d[0] == 3:
        print(M[-1])