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

using ll = long long;
using pll = pair<ll,ll>;
const ll NEG = -(1LL << 60);

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    ll N, M;
    cin >> N >> M;

    vector<pll> VW(N);
    for (auto &[v, w] : VW) cin >> v >> w;

    sort(VW.rbegin(), VW.rend()); // 美しさ降順

    vector<ll> dp(M + 1, NEG);
    dp[0] = 0;

    ll ans = 0;
    ll best = 0; // 現時点での美しさ総和の最大値

    for (auto [v, w] : VW) {
        for (ll j = M - w; j >= 0; --j) {
            if (dp[j] == NEG) continue;
            dp[j + w] = max(dp[j + w], dp[j] + v);
            best = max(best, dp[j + w]);
        }
        ans = max(ans, v * best);
    }

    cout << ans << '\n';
    return 0;
}