蒟蒻求助，不胜感激，呜呜喵

#include<bits/stdc++.h>

using namespace std;
using ll=long long;
ll n,c,sum;
vector<ll>v;
void solve() {
    for (int i = 0; i < n; i++) {
        auto m = lower_bound(v.begin() + i+1, v.end(), c+v[i]);
        if (m != v.end()) {
            sum++;
            while (m + 1 != v.end() && *(m + 1) == *m){
                m = m + 1;
                sum++;
            }
        }
    }
    cout << sum << endl;
}
int main(){
    ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
    cin>>n>>c;
    v.resize(n);
    for(ll i=0;i<n;i++) cin>>v[i];
    sort(v.begin(),v.end());
    solve();
    return 0;
}