#include <bits/stdc++.h>
using namespace std;
 
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
 
    int N;
    long long W;
    if (!(cin >> N >> W)) return 0;
 
    vector<pair<long long,long long>> a(N); // (w, v)
    for (int i = 0; i < N; ++i) {
        long long v, w;
        cin >> v >> w;
        a[i] = {w, v};
    }
    sort(a.begin(), a.end()); // sort by weight asc
 
    // Gom theo trọng lượng
    struct Group { long long w; vector<long long> vals; };
    vector<Group> g;
    for (auto [w, v] : a) {
        if (g.empty() || g.back().w != w) g.push_back({w, {}});
        g.back().vals.push_back(v);
    }
 
    priority_queue<long long> pq;
    long long ans = 0;
    long long usedSlots = 0; // số slot đã dùng theo đơn vị w_{i} của vòng lặp hiện tại
 
    for (int i = (int)g.size() - 1; i >= 0; --i) {
        // Chuyển đơn vị slot từ w_{i+1} xuống w_i: nhân với r = w_{i+1}/w_i
        if (i + 1 < (int)g.size()) {
            long long r = g[i + 1].w / g[i].w;
            // đảm bảo không vượt quá floor(W / w_i)
            long long Ti = W / g[i].w;
            __int128 scaled = (__int128)usedSlots * r;
            if (scaled > Ti) usedSlots = Ti;
            else usedSlots = (long long)scaled;
        }
 
        // Thêm các món có đúng trọng lượng w_i
        for (long long v : g[i].vals) pq.push(v);
 
        long long Ti = W / g[i].w;           // tối đa slot đơn vị w_i có thể dùng
        long long add = Ti - usedSlots;      // còn có thể lấp thêm bao nhiêu slot
        while (add > 0 && !pq.empty()) {
            ans += pq.top(); pq.pop();
            ++usedSlots; --add;
        }
    }
 
    cout << ans << '\n';
    return 0;
}
 

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

NiAxMAoxIDEKNiAyCjIwIDYKOCAyCjUgMgoxMCAxCg==

6 10
1 1
6 2
20 6
8 2
5 2
10 1