#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
using ld = long double;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    int N,M; cin >> N >> M;
    vector<pair<int,int>> J(N);
    for(auto &[v, w] : J) cin >> v >> w;
    sort(J.begin(), J.end(), [&](pair<int,int> L, pair<int,int> R) {
        auto [vL, wL] = L;
        auto [vR, wR] = R;
        if(vL != vR) return vL > vR;
        return wL < wR;
    });

    vector<ll> dp(M + 1, 0);
    ll ans = 0;
    for(auto [v, w] : J) {
        vector<ll> nt = dp;
        for(int k = 0; k <= M; k++) {
            if(k + w <= M)
                nt[k + w] = max(nt[k + w], dp[k] + v);
        }
        swap(dp, nt);
        ans = max(ans, *max_element(dp.begin(), dp.end()) * v);
    }
    cout << ans << endl;
}