#include <fstream>
#include <algorithm>
#include <iostream>

using namespace std;

ifstream f("energii.in");
ofstream g("energii.out");

struct energie
{
    int p,n;
};

int ordo(energie a, energie b)
{
    return(a.n<b.n);
}

int n,w,i,st,dr,s,c,ok,minn;
energie E[1001];
int main()
{
    f>>n>>w;
    for(i=1;i<=n;i++)
    {
        f>>E[i].p>>E[i].n;
        minn+=E[i].n;
    }
    sort(E+1,E+n+1,ordo);
    /*for(i=1;i<=n;i++)
        g<<E[i].p<<" "<<E[i].n<<'\n';*/
    st=dr=1;
    ok=1;
    s+=E[dr].p;
    c+=E[dr].n;
    while(ok!=0)
    {
        if(s>=w)
        {
            minn=min(minn,c);
            c-=E[st].n;
            s-=E[st].p;
            st++;
        }
        else
        {
            if(dr==n)
                ok=0;
            else
            {
                dr++;
                s+=E[dr].p;
                c+=E[dr].n;
            }
        }
    }
    g<<minn;
    f.close();
    g.close();
    return 0;
}