# 暴力枚举的水题 数据说明最大数不超过1e5所以用桶排序
# 即使超过也可用字典来储存list排序 记住最大最小值即可
n = int(input())
tong = [0 for x in range(100010)]
ERR = -1
minN, maxN = 0x3f3f3f3f, -1
while n:
for j in map(int, input().split()):
if tong[j] == 1:
ERR = j
tong[j] += 1
minN = min(j, minN)
maxN = max(j, maxN)
n -= 1
# 易错得从最小值开始找 不能从1开始
for i in range(minN, maxN + 1):
if tong[i] == 0:
print(i, ERR)
break
$O(n)=10^{5}*2$