#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll INF = 1001001001001001001LL;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int n, m;
    cin >> n >> m;
    vector<pair<int, int>> card;
    ll ans = 0;
    
    for (int i = 0; i < n; i++) {
        int c, d;
        cin >> c >> d;
        if (c == 0) {
            ans += d;
            continue;
        }
        card.emplace_back(c, d);
    }
    
    sort(card.rbegin(), card.rend());
    
    vector<vector<ll>> dp(11, vector<ll>(m + 1, -INF));
    dp[0][0] = 0;
    
    for (auto [c, d] : card) {
        auto ndp = dp;
        int mul = 1 << 9;
        for (int p = 9; p >= 0; --p) {
            for (int nc = m - mul * c; nc >= 0; --nc) {
                ndp[p + 1][nc + mul * c] = max(ndp[p + 1][nc + mul * c], dp[p][nc] + d);
            }
            mul /= 2;
        }
        dp = ndp;
    }
    
    ll tmp = -INF;
    for (int i = 0; i < 10; i++) {
        tmp = max(*max_element(dp[i].begin(), dp[i].end()), tmp);
    }
    
    cout << ans + tmp << '\n';
    return 0;
}