## LCC/Moose '20 Contest 3 J1 - Cup Swapping

View as PDF

Points: 3
Time limit: 2.0s
Memory limit: 64M

Author:
Problem type

You have cups in a line. Only one of these cups will contain a ball, and the ball will be in the . cup from the left. Your friend decides to mess with you, and while you weren't looking they swapped two cups at random, times. However, you had a camera that was able to keep track of all of the switches. Using this, can you determine which cup contains the ball after the switches, counting from left to right?

#### Input Specification

The first line will contain , the number of swaps that your friend made, and , the cup that contains the ball counting from the left.

The next lines will each contain 2 integers, and , the cups that were swapped by your friend in the specific swap.

#### Output Specification

One integer, the index of the cup that contains the ball, counting from the left.

#### Sample Input 1

3 1
1 2
2 3
1 2

#### Sample Output 1

3

#### Sample Explanation

The ball starts off in cup . After the first swap, the ball is now in cup . After the second, the ball is now in cup . The third swap does not affect which ball the cup is in, so finally the answer is .