#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 1000000007;
// constexpr int MOD = 998244353;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  int n, m; cin >> n >> m;
  vector<int> v(n), w(n); REP(i, n) cin >> v[i] >> w[i];
  vector<int> jewelry(n);
  iota(ALL(jewelry), 0);
  sort(ALL(jewelry), [&](int a, int b) -> bool { return v[a] > v[b]; });
  vector<ll> dp(m + 1, 0);
  ll ans = 0;
  for (int i : jewelry) {
    for (int j = m - w[i]; j >= 0; --j) {
      if (chmax(dp[j + w[i]], dp[j] + v[i])) chmax(ans, dp[j + w[i]] * v[i]);
    }
  }
  cout << ans << '\n';
  return 0;
}