A12051. Session in BSU
编程题
普及/提高-
知识点
题目描述
The first line of the input contains one integer $n$ ( $1 \le n \le 10^6$ ) — the number of exams.
The next $n$ lines contain two integers each: $a_i$ and $b_i$ ( $1 \le a_i < b_i \le 10^9$ ), where $a_i$ is the number of day of the first passing the $i$ -th exam and $b_i$ is the number of day of the second passing the $i$ -th exam.
The next $n$ lines contain two integers each: $a_i$ and $b_i$ ( $1 \le a_i < b_i \le 10^9$ ), where $a_i$ is the number of day of the first passing the $i$ -th exam and $b_i$ is the number of day of the second passing the $i$ -th exam.
输入格式
If Polycarp cannot pass all the $n$ exams, print -1. Otherwise print the minimum index of day by which Polycarp can do that.
输出格式
无
输入输出样例
输入 #1
2 1 5 1 7
输出 #1
5
输入 #2
3 5 13 1 5 1 7
输出 #2
7
输入 #3
3 10 40 40 80 10 80
输出 #3
80
输入 #4
3 99 100 99 100 99 100
输出 #4
-1