import java.util.*;

public class Main {
    static final int MOD = 1000000007;
	public static void main (String[] args) {
    	Scanner sc = new Scanner(System.in);
    	int n = sc.nextInt();
    	int k = sc.nextInt();
    	int[] arr = new int[n];
    	for (int i = 0; i < n; i++) {
    	    arr[i] = sc.nextInt();
    	}
    	Arrays.sort(arr);
    	long ans = 1;
    	if (k - arr[n - 1] < arr[0]) {
    	    System.out.println(0);
    	    return;
    	}
    	int right = n - 1;
    	int left = 0;
    	int count = 0;
    	while (right >= n / 2) {
    	    while (left + 1 < right && k - arr[right] >= arr[left + 1]) {
    	        left++;
    	    }
    	    if (left + 1 <= count) {
    	        System.out.println(0);
    	        return;
    	    }
    	    ans *= left + 1 - count;
    	    ans %= MOD;
    	    count++;
    	    right--;
    	    left = Math.min(left, right - 1);
    	}
    	System.out.println(ans);
	}
}