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

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int N;
    long long W;
    cin >> N >> W;
    
    vector<pair<int,int>> items(N);
    int maxW = 0;
    for (int i = 0; i < N; ++i) {
        int v,w; cin >> v >> w;
        items[i] = {v,w};
        maxW = max(maxW, w);
    }
    
    int B = maxW;
    long long W0 = min(W, 1LL * B * B);
    vector<long long> dp(W0 + 1, 0);
    for (int i = 0; i < N; ++i) {
        int v = items[i].first;
        int w = items[i].second;
        for (int c = w; c <= W0; ++c) {
            dp[c] = max(dp[c], dp[c - w] + v);
        }
    }
    
    if (W <= W0) {
        cout << dp[W] << '\n';
        return 0;
    }
    
    int idx = 0;
    for (int i = 1; i < N; ++i) {
        long long vi = items[i].first, wi = items[i].second;
        long long vj = items[idx].first, wj = items[idx].second;
        if (vi * wj > vj * wi) idx = i;
    }
    long long vk = items[idx].first;
    long long wk = items[idx].second;
    long long maxX = W / wk;
    long long minX;
    minX = (W - W0 + wk - 1) / wk;
    if (minX < 0) minX = 0;
    if (minX > maxX) {
        long long ans = 0;
        for (long long x = 0; x <= maxX; ++x) {
            long long rem = W - x*wk;
            if (rem <= W0) {
                long long cand = dp[rem] + x * vk;
                ans = max(ans, cand);
            }
        }
        cout << ans << '\n';
        return 0;
    }
    
    long long ans = 0;
    for (long long x = minX; x <= maxX; ++x) {
        long long rem = W - x * wk; 
        if (rem < 0 || rem > W0) continue;
        long long cand = dp[rem] + x * vk;
        ans = max(ans, cand);
    }
    
    cout << ans << '\n';
    
    return 0;
}