#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
constexpr ll mod = 1e9 + 7;
constexpr ll INF = (1LL << 62) - (1LL << 31) - 1;

#define REP(i, init, n) for(int i = (int)(init); i < (int)(n); i++)
#define RREP(i, init, n) for(int i = (int)(init); i >= (int)(n); i--)
#define All(A) A.begin(), A.end()
#define rAll(A) A.rbegin(), A.rend()

#define vi vector<int>
#define vl vector<long>
#define vvi vector<vector<int>>
#define vvl vector<vector<long>>
#define pint pair<int, int>
#define plong pair<long, long>

int N, W;
vector<plong> P;

void solve() {
    long ans = 0;
    long tmp_max_val = 0, tmp_idx = -1, max_count = 0;
    REP(i, 0, N) {
        long count = (long)(W - 20000) / P[i].second;
        long tmp_val = count * P[i].first;
        if(tmp_max_val < tmp_val) {
            tmp_max_val = tmp_val;
            tmp_idx = i;
            max_count = count;
        }
    }

    // cerr << tmp_max_val << " " << tmp_idx << " " << max_count << endl;
    if(tmp_idx != -1) {
        ans += P[tmp_idx].first * max_count;
        W -= P[tmp_idx].second * max_count;
    }

    vvl dp(N + 1, vl(W + 1, -1));
    dp[0][W] = 0;
    REP(i, 0, N) {
        long pv = P[i].first;
        long pw = P[i].second;
        RREP(w, W, 0) {
            if(dp[i][w] != -1) {
                dp[i + 1][w] = max(dp[i + 1][w], dp[i][w]);
            }
            if(w + pw <= W && dp[i][w + pw] != -1) {
                dp[i + 1][w] = max(dp[i + 1][w], dp[i][w + pw] + pv);
            }
            if(w + pw <= W && dp[i + 1][w + pw] != -1) {
                dp[i + 1][w] = max(dp[i + 1][w], dp[i + 1][w + pw] + pv);
            }
        }
    }
    /*
    REP(i, 0, N + 1) {
        REP(j, 0, W + 1) {
            cerr << dp[i][j] << " ";
        }
        cerr << endl;
    }
    */

    long max_table = 0;
    REP(i, 0, N + 1) {
        REP(j, 0, W + 1) {
            max_table = max(max_table, dp[i][j]);
        }
    }
    ans += max_table;
    cout << ans << endl;
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    cin >> N >> W;
    P.resize(N);
    REP(i, 0, N) {
        cin >> P[i].first >> P[i].second;
    }
    solve();
}