#include <fstream>

using namespace std;
ifstream fin ("energii.in");
ofstream fout ("energii.out");
int n,g,i,j,a,b,v[5001];
int main()
{
    fin>>n>>g;

    for(i=1;i<=n;i++)
    {
        fin>>a>>b;

        for(j=5001-b;j>=0;j--)
        {
            if(v[j-b+1]!=0 || j==0)
            v[j]=max(v[j],v[j-b+1]+a);
        }
    }
    for(i=1;i<=5001;i++)
    {
        if(v[i]>=g)
            fout<<v[i];
        return 0;
    }
    return 0;
}