s = list(map(int,input().split()))
ss = list(map(int,input().split()))
sss = {}
ans = 0
for i in ss:
        if i not in sss:
                sss[i] = 1
        else:
                sss[i] += 1

for a,b in sss.items():
        if s[1] - a in sss:
                ans += b * sss[s[1]-a]

print(ans)