#include "bits/stdc++.h" using namespace std; #define ll long long int int a[100001]; int main() { cin.tie(0); ios::sync_with_stdio(false); ll x; int n,c=0,p,m=0; cin >> n >> x; for (int i=0;i>p; a[p]++; m=m=m) c+=a[x-i]*a[i]; } cout << c << endl; return 0; }