Kefa and Company

#include <bits/stdc++.h>
using namespace std;

#define read(vec, n) for(int i = 0 ; i < n && cin >> vec[i] ; i++);
#define print(v, template) copy(all(v), ostream_iterator <template> (cout, " "));
#define read_2d(vec, n, m) for(int i = 0; i < n; i++) for(int j = 0; j < m && cin >> nums[i][j]; j++);
#define loop(a, b, c) for(int i = a ; i < (b); i += c)
#define all(vec) vec.begin(),vec.end()
#define rall(vec) vec.rbegin(),vec.rend()
#define Vector vector <int>
#define Map map <int,int>
#define Set set <int>
#define Pair pair <int,int>
#define ll long long
#define ull unsigned long long
#define Mod 1000000007
#define PI 3.14159

void Code_Crush(){
  ios_base::sync_with_stdio(false);   cin.tie(nullptr);   cout.tie(nullptr);
#ifndef ONLINE_JUDGE
  freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#endif
}

int main(){
    Code_Crush();
    int n, d, i = 0;
    ll Max_friendship = INT_MIN, Max_friend = 0;
    cin >> n >> d;
    vector <pair<int, int>> companies(n);
    for(auto& [f, s] : companies) cin >> f >> s;
    sort(all(companies));
    for(int i = 0, j = 0; i < n; i++){
      Max_friend += companies[i].second;
      while(companies[i].first - companies[j].first >= d) Max_friend -= companies[j++].second;
      Max_friendship = max(Max_friend, Max_friendship);
    }
    cout << Max_friendship;
    return 0;
}