n = int(input())

start = []
end = []
all = []


for i in range(n):
    s, e = map(int, input().split())
    tup1 = (s, "(")
    tup2 = (e, ")")
    all.append(tup1)
    all.append(tup2)

all = sorted(all)
# print(all)

stack = []
star = 0
stop = 0

for i in range(n):
    if all[i][1] == "(":
        stack.append(all[i][0])
    elif all[i][1] == ")":
        star = stack[0]
        stack.pop()
    if len(stack) == 0:
        print(star, all[i][1])