Problem:
Score : 200 points

Problem Statement

There are N + 1 squares arranged in a row, numbered 0, 1, ..., N from left to right.

Initially, you are in Square X.
You can freely travel between adjacent squares. Your goal is to reach Square 0 or Square N.
However, for each i = 1, 2, ..., M, there is a toll gate in Square A_i, and traveling to Square A_i incurs a cost of 1.
It is guaranteed that there is no toll gate in Square 0, Square X and Square N.

Find the minimum cost incurred before reaching the goal.

Constraints

1 \leq N \leq 100

1 \leq M \leq 100

1 \leq X \leq N - 1

1 \leq A_1 < A_2 < ... < A_M \leq N

A_i \neq X

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N M X
A_1 A_2 ... A_M

Output

Print the minimum cost incurred before reaching the goal.

Sample Input 1

5 3 3
1 2 4

Sample Output 1

1

The optimal solution is as follows:

First, travel from Square 3 to Square 4. Here, there is a toll gate in Square 4, so the cost of 1 is incurred.

Then, travel from Square 4 to Square 5. This time, no cost is incurred.

Now, we are in Square 5 and we have reached the goal.

In this case, the total cost incurred is 1.

Sample Input 2

7 3 2
4 5 6

Sample Output 2

0

We may be able to reach the goal at no cost.

Sample Input 3

10 7 5
1 2 3 4 6 8 9

Sample Output 3

3

Solution in C (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
int main()
{
    int n, m, x;
    scanf("%d %d %d", &n, &m, &x);
    int a[100];
    int i;
    for (i = 0; i < m; i++)
        scanf("%d", &a[i]);
    int k;
    for(i=0;i<m-1;i++)
        if (a[i] > a[i + 1])
        {
            k = a[i];
            a[i] = a[i + 1];
            a[i + 1] = k;
            if (i != 0)
                i -= 2;
        }
    int ans1, ans2;
    ans1 = ans2 = 0;
    i = 0;
    while (a[i] < x)
    {
        ans1++;
        i++;
    }
    while (i < m)
    {
        ans2++;
        i++;
    }
    if (ans1 > ans2)
        ans1 = ans2;
    printf("%d\n", ans1);
    return 0;
}