#include<bits/stdc++.h>
using namespace std;
#define P pair<int,int>
int n,W,suf,i,j,k,VMAX,x,y,z,t;
P obj[5002],sufpart[5002];
class I
{
    private:
        FILE *F;
        char *buff;
        int sp;
        char read_ch()
        {
            ++sp;
            if (sp == 4096) {
                sp = 0;
                fread(buff, 1, 4096, F);
            }
            return buff[sp];
        }
    public:
        I(const char* nume)
        {
            F = fopen(nume, "r");
            buff = new char[4096]();
            sp = 4095;
        }
        I& operator >> (int &n)
        {
            char c;
            for(c=read_ch();!isdigit(c);c=read_ch());
            for(n=0;isdigit(c);n=10*n+c-'0',c=read_ch());
            return *this;
        }
};
int greedsuf(int poz,int wmax)
{
    int rez=0;
    while(poz<n&&obj[poz].first<wmax)
        rez+=obj[poz].second,wmax-=obj[poz++].first;
    if(poz==n)
        return rez;
    return rez+obj[poz].second*wmax/obj[poz].first;
}
void B(int poz,int vtot,int rem)
{
    if(poz==n)
        VMAX=max(VMAX,vtot);
    else {
        if(rem-obj[poz].first>=0&&vtot+obj[poz].second+greedsuf(poz+1,rem-obj[poz].first)>VMAX)
            B(poz+1,vtot+obj[poz].second,rem-obj[poz].first);
        if(vtot+greedsuf(poz+1,rem)>VMAX)
            B(poz+1,vtot,rem);
    }
}
bool A(P a,P b)
{
    return a.second*b.first>=b.second*a.first;
}
int main()
{
    I F("rucsac.in");
    ofstream G("rucsac.out");
    for(F>>n>>W;i<n;F>>obj[i].first>>obj[i].second,++i);
    for(sort(obj,obj+n,A),obj[n].first=1,i=n-1;i>=0;sufpart[i]=make_pair(sufpart[i+1].first+obj[i].first,sufpart[i+1].second+obj[i].second),--i);
    for(i=0;i<n&&x+obj[i].first<=W;x+=obj[i].first,VMAX+=obj[i++].second);
    return B(0,0,W),G<<VMAX,0;
}