// URL: https://yukicoder.me/problems/no/626

import std.algorithm, std.array, std.bitmanip, std.container, std.conv, std.format,
       std.functional, std.math, std.range, std.traits, std.typecons, std.stdio, std.string;

version(unittest) {} else
void main()
{
  int n; long tw; io.getV(n, tw);
  C[] c; io.getS!("v", "w")(n, c);

  c.sort!((a, b) => a.v.to!double/a.w > b.v.to!double/b.w);

  auto p = 0L;

  auto lowerUpper(int i, C s)
  {
    auto u = 0.0L;
    foreach (j; i..n) {
      if (s.w < c[j].w) {
        u = s.v + c[j].v.to!double/c[j].w*s.w;
        break;
      }
      s += c[j];
    }
    return tuple(s.v, max(u.floor.to!long, s.v));
  }

  auto dfs(int i, C s)
  {
    if (i == n) return;

    auto lu = lowerUpper(i, s);
    if (lu[1] < p) return;
    p.maxU(lu[0]);

    dfs(i+1, s);
    if (s.w >= c[i].w) dfs(i+1, s+c[i]);
  }

  dfs(0, C(0, tw));

  io.put(p);
}

struct C
{
  long v, w;
  auto opBinary(string op: "+")(C a) { return C(v+a.v, w-a.w); }
  auto opOpAssign(string op: "+")(C a) { v += a.v; w -= a.w; return this; }
}

pragma(inline) pure nothrow @nogc @safe
{
  T minU(T, U)(ref T a, U b)
  { return a = min(a, b); }
  T maxU(T, U)(ref T a, U b)
  { return a = max(a, b); }
}

auto io = IO!()();
import std.stdio;
struct IO(alias IN = stdin, alias OUT = stdout)
{
  import std.meta : allSatisfy;
  import core.stdc.stdlib : exit;

  void getV(T...)(ref T v)
  {
    foreach (ref w; v) get(w);
  }
  void getA(T)(size_t n, ref T v)
    if (hasAssignableElements!T)
  {
    v = new T(n);
    foreach (ref w; v) get(w);
  }
  void getC(T...)(size_t n, ref T v)
    if (allSatisfy!(hasAssignableElements, T))
  {
    foreach (ref w; v) w = new typeof(w)(n);
    foreach (i; 0..n) foreach (ref w; v) get(w[i]);
  }
  void getM(T)(size_t r, size_t c, ref T v)
    if (hasAssignableElements!T && hasAssignableElements!(ElementType!T))
  {
    v = new T(r);
    foreach (ref w; v) getA(c, w);
  }
  template getS(E...)
  {
    void getS(T)(size_t n, ref T v)
    {
      v = new T(n);
      foreach (ref w; v) foreach (e; E) mixin("get(w."~e~");");
    }
  }

  const struct PutConf
  {
    bool newline = true, flush, exit;
    string floatFormat = "%.10f", delimiter = " ";
  }

  void put(alias conf = "{}", T...)(T v)
  {
    mixin("const PutConf c = "~conf~"; putMain!c(v);");
  }
  void putB(alias conf = "{}", S, T)(bool c, S t, T f)
  {
    if (c) put!conf(t);
    else put!conf(f);
  }
  void putRaw(T...)(T v)
  {
    OUT.write(v);
    OUT.writeln;
  }

  private
  {
    dchar[] buf;
    auto sp = (new dchar[](0)).splitter;

    void nextLine()
    {
      IN.readln(buf);
      sp = buf.splitter;
    }
    void get(T)(ref T v)
    {
      if (sp.empty) nextLine();
      v = sp.front.to!T;
      sp.popFront();
    }

    void putMain(PutConf c, T...)(T v)
    {
      foreach (i, w; v) {
        putOne!c(w);
        if (i+1 < v.length) OUT.write(c.delimiter);
      }
      static if (c.newline) OUT.writeln;
      static if (c.flush) OUT.flush();
      static if (c.exit) exit(0);
    }
    void putOne(PutConf c, T)(T v)
    {
      static if (isInputRange!T && !isSomeString!T) putRange!c(v);
      else static if (isFloatingPoint!T) OUT.write(format(c.floatFormat, v));
      else static if (hasMember!(T, "fprint")) v.fprint(OUT);
      else OUT.write(v);
    }
    void putRange(PutConf c, T)(T v)
    {
      auto w = v;
      while (!w.empty) {
        putOne!c(w.front); w.popFront();
        if (!w.empty) OUT.write(c.delimiter);
      }
    }
  }
}