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.

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.

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.

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

见题面 Input 部分

见题面 Output 部分