#include<bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include <debug.hpp>
#define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (static_cast<void>(0))
#endif
// #pragma GCC target("avx,avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pll = pair<ll,ll>;
using pii = pair<int,int>;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vul = vector<ull>;
using vpii = vector<pii>;
using vvpii = vector<vpii>;
using vpll = vector<pll>;
using vs = vector<string>;
template<class T> using pq = priority_queue<T,vector<T>, greater<T>>;
#define overload4(_1, _2, _3, _4, name, ...) name
#define overload3(a,b,c,name,...) name
#define rep1(n) for (ll UNUSED_NUMBER = 0; UNUSED_NUMBER < (n); ++UNUSED_NUMBER)
#define rep2(i, n) for (ll i = 0; i < (n); ++i)
#define rep3(i, a, b) for (ll i = (a); i < (b); ++i)
#define rep4(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)
#define rrep1(n) for(ll i = (n) - 1;i >= 0;i--)
#define rrep2(i,n) for(ll i = (n) - 1;i >= 0;i--)
#define rrep3(i,a,b) for(ll i = (b) - 1;i >= (a);i--)
#define rrep4(i,a,b,c) for(ll i = (a) + (((b)-(a)-1) / (c) - (((b)-(a)-1) % (c) && (((b)-(a)-1) ^ c) < 0)) * (c);i >= (a);i -= c)
#define rrep(...) overload4(__VA_ARGS__, rrep4, rrep3, rrep2, rrep1)(__VA_ARGS__)
#define all1(i) begin(i) , end(i)
#define all2(i,a) begin(i) , begin(i) + a
#define all3(i,a,b) begin(i) + a , begin(i) + b
#define all(...) overload3(__VA_ARGS__, all3, all2, all1)(__VA_ARGS__)
#define sum(...) accumulate(all(__VA_ARGS__),0LL)
template<class T> bool chmin(T &a, const T &b){ if(a > b){ a = b; return 1; } else return 0; }
template<class T> bool chmax(T &a, const T &b){ if(a < b){ a = b; return 1; } else return 0; }
template<class T> auto min(const T& a){return *min_element(all(a));}
template<class T> auto max(const T& a){return *max_element(all(a));}
template<class... Ts> void in(Ts&... t);
#define INT(...) int __VA_ARGS__; in(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__; in(__VA_ARGS__)
#define STR(...) string __VA_ARGS__; in(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__; in(__VA_ARGS__)
#define DBL(...) double __VA_ARGS__; in(__VA_ARGS__)
#define LD(...) ld __VA_ARGS__; in(__VA_ARGS__)
#define VEC(type, name, size) vector<type> name(size); in(name)
#define VV(type, name, h, w) vector<vector<type>> name(h, vector<type>(w)); in(name)
ll intpow(ll a, ll b){ll ans = 1; while(b){if(b & 1) ans *= a; a *= a; b /= 2;} return ans;}
ll modpow(ll a, ll b, ll p){ ll ans = 1; a %= p;if(a < 0) a += p;while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; }
bool is_clamp(ll val,ll low,ll high) {return low <= val && val < high;}
void Yes() {cout << "Yes\n";return;}
void No() {cout << "No\n";return;}
void YES() {cout << "YES\n";return;}
void NO() {cout << "NO\n";return;}
template <typename U,typename T>
U floor(U a, T b) {return a / b - (a % b && (a ^ b) < 0);}
template <typename U,typename T>
U ceil(U x, T y) {return floor(x + y - 1, y);}
template <typename U,typename T>
T bmod(U x, T y) {return x - y * floor(x, y);}
template <typename U,typename T>
pair<U, T> divmod(U x, T y) {U q = floor(x, y);return {q, x - q * y};}
namespace IO{
#define VOID(a) decltype(void(a))
struct setting{ setting(){cin.tie(nullptr); ios::sync_with_stdio(false);fixed(cout); cout.precision(15);}} setting;
template<int I> struct P : P<I-1>{};
template<> struct P<0>{};
template<class T> void i(T& t){ i(t, P<3>{}); }
void i(vector<bool>::reference t, P<3>){ int a; i(a); t = a; }
template<class T> auto i(T& t, P<2>) -> VOID(cin >> t){ cin >> t; }
template<class T> auto i(T& t, P<1>) -> VOID(begin(t)){ for(auto&& x : t) i(x); }
template<class T, size_t... idx> void ituple(T& t, index_sequence<idx...>){in(get<idx>(t)...);}
template<class T> auto i(T& t, P<0>) -> VOID(tuple_size<T>{}){ituple(t, make_index_sequence<tuple_size<T>::value>{});} 
#undef VOID
}
#define unpack(a) (void)initializer_list<int>{(a, 0)...}
template<class... Ts> void in(Ts&... t){ unpack(IO :: i(t)); }
#undef unpack
constexpr long double PI = 3.141592653589793238462643383279L;
template <class F> struct REC {
    F f;
    REC(F &&f_) : f(forward<F>(f_)) {}
    template <class... Args> auto operator()(Args &&...args) const { return f(*this, forward<Args>(args)...); }};

constexpr int mod = 998244353;
//constexpr int mod = 1000000007;

using i64 = long long;
struct Item {
    i64 W, V, M;
};

i64 knapsack_8(i64 Z, vector<Item> items) {
    for (auto &a : items) {
        Item &t = items.back();
        __int128 lhs = (__int128)a.V * t.W;
        __int128 rhs = (__int128)t.V * a.W;
        if (lhs > rhs) swap(a, t); 
    }
    Item top = items.back();
    items.pop_back();  

    i64 Wp = top.W;
    i64 Vp = top.V;

    i64 q = Z / Wp;
    i64 R = Z % Wp;

    const i64 NEG = (i64)-4e18;
    vector<i64> dp(Wp, NEG);
    dp[0] = 0;

    for (auto &it : items) {
        i64 Wi = it.W;
        i64 Vi = it.V;

        vector<i64> gain(Wp);
        for (i64 r = 0; r < Wp; ++r) {
            i64 delta = (r + Wi) / Wp; 
            gain[r] = Vi - delta * Vp;
        }

        vector<char> used(Wp, 0);

        for (i64 start = 0; start < Wp; ++start) {
            if (used[start]) continue;

            vector<i64> cyc;
            i64 r = start;
            while (!used[r]) {
                used[r] = 1;
                cyc.push_back(r);
                r = (r + Wi) % Wp;
            }

            int L = (int)cyc.size();
            vector<i64> best(L);
            for (int j = 0; j < L; ++j) {
                best[j] = dp[cyc[j]];
            }
            for (int t = 0; t < 2 * L; ++t) {
                int j = t % L;
                int prev = (j - 1 + L) % L;
                i64 prevRem = cyc[prev];
                if (best[prev] <= NEG / 2) continue;
                i64 cand = best[prev] + gain[prevRem];
                if (cand > best[j]) best[j] = cand;
            }
            for (int j = 0; j < L; ++j) {
                dp[cyc[j]] = best[j];
            }
        }
    }
    i64 bestOffset = NEG;
    for (i64 r = 0; r < Wp; ++r) {
        if (dp[r] <= NEG / 2) continue;
        int delta_z = (r <= R ? 0 : 1);
        i64 val = dp[r] - (i64)delta_z * Vp;
        if (val > bestOffset) bestOffset = val;
    }
    if (bestOffset < NEG / 2) bestOffset = 0;

    i64 ans = q * Vp + bestOffset;
    return ans;
}

void solve() {
    INT(n,W);
    vi v(n),w(n);
    rep(i,n) cin >> v[i] >> w[i];
    vector<Item> V(n);
    rep(i,n) V[i] = {w[i],v[i],(ll)1e18};
    if(W > 1000 * 1000) {
        cout << knapsack_8(W,V) << '\n';
    }
    else {
        vl dp(W+1);
        rep(i,n) {
            rep(j,W+1-w[i]) {
                chmax(dp[j+w[i]],dp[j]+v[i]);
            }
        }
        cout << dp[W] << '\n';
    }
}
int main() {
    //INT(TT);
    int TT = 1;
    rep(i,TT) solve();
}