//愚直解

#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <stdio.h>
#define MAX_DATA 300000
#define ll long long

int main(void) {
    int n, m;
    scanf("%d", &n);    scanf("%d", &m);

    int a[MAX_DATA];
    for(int i = 0; i < n; ++i){
        scanf("%d", &a[i]);
    }

    if(m & 1){
        puts("0");
        return 0;
    }

    int cnt = 0;
    int h = m / 2;
    for(int i = 0; i < n - 1; ++i){
        for(int j = i + 1; j < n; ++j){
            int x = a[i] - a[j];
            if(x == h || x == -h){
                ++cnt;
            }
        }
    }
    ll ans = (ll)cnt * (n - 2);
    printf("%lld\n", ans);
    
	return 0;
}