#include <fstream>

using namespace std;

int p[5001],g[5001],v[10001];

int main()
{
    ifstream in("rucsac.in");
    ofstream out("rucsac.out");
    int i,j,k,n;

    in>>n>>k;
    for(i=1;i<=n;i++) in>>g[i]>>p[i];

    //v[0]=0;
    //for(i=1;i<=k;i++) v[i]=-1;

    for(i=1;i<=n;i++)
        for(j=k-g[i];j>=0;j--)
        {
            if(v[j]!=-1 && v[j]+p[i]>v[j+g[i]])
                v[j+g[i]]=v[j]+p[i];
        }

    out<<v[k]<<"\n";

}