Problem:
Score : 500 points

Problem Statement

There are N integers X_1, X_2, \cdots, X_N, and we know that A_i \leq X_i \leq B_i.
Find the number of different values that the median of X_1, X_2, \cdots, X_N can take.

Notes

The median of X_1, X_2, \cdots, X_N is defined as follows. Let x_1, x_2, \cdots, x_N be the result of sorting X_1, X_2, \cdots, X_N in ascending order.

If N is odd, the median is x_{(N+1)/2};

if N is even, the median is (x_{N/2} + x_{N/2+1}) / 2.

Constraints

2 \leq N \leq 2 \times 10^5

1 \leq A_i \leq B_i \leq 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
A_1 B_1
A_2 B_2
:
A_N B_N

Output

Print the answer.

Sample Input 1

2
1 2
2 3

Sample Output 1

3

If X_1 = 1 and X_2 = 2, the median is \frac{3}{2};

if X_1 = 1 and X_2 = 3, the median is 2;

if X_1 = 2 and X_2 = 2, the median is 2;

if X_1 = 2 and X_2 = 3, the median is \frac{5}{2}.

Thus, the median can take three values: \frac{3}{2}, 2, and \frac{5}{2}.

Sample Input 2

3
100 100
10 10000
1 1000000000

Sample Output 2

9991

Solution in Python (3.8.2) (judge verdict: Wrong Answer)

import sys
readline = sys.stdin.readline
# generator = (readline().strip() for _ in range(N))

# N, M = map(int, input().split())
# As = list(map(int, input().split()))
# queries = (input() for _ in range(N))


def solve():
    N = int(input())
    generator = (map(int, readline().strip().split()) for _ in range(N))

    As = [0] * N
    Bs = [0] * N

    i = 0
    for a, b in generator:
        As[i] = a
        Bs[i] = b
        i += 1

    As.sort()
    Bs.sort(reverse=True)

    if N & 1:
        center = N // 2
    else:
        center = (N-1) // 2

    ac = As[center]
    bc = Bs[center]
    p = bc - ac + 1
    return p


def main():
    print(solve())


if __name__ == "__main__":
    main()