#include <bits/stdc++.h>
using namespace std;
int main(){
int count = 0;
int n,x;
cin >> n >> x;
int A[n];
for (int i = 0; i < n; i++){
cin >> A[i];
}
sort(A, A + n);
int f = 0;
int e = n -1;
while (e >= f){
if (A[f] + A[e] == x){
count++;
f++;
}
else if (A[f] + A[e] > x){
e--;
}
else{
f++;
}
}
cout << count;
}
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