#include <fstream>
using namespace std;
ifstream in("rucsac.in");
ofstream out("rucsac.out");

int n, k, p[5001], g[10001], profit[10001], i, j;

int main()
{
    in>>n>>k;
    for(i=1;i<=n;i++)
        in>>g[i]>>p[i];
    for(i=1;i<=k;i++) profit[i]=-1;
    profit[0]=0;
    for(i=1;i<=n;i++)
        for(j=k-g[i];j>=0;j--)
            if(profit[j]!=-1 && profit[j]+p[i]>profit[j+g[i]])
                profit[j+g[i]]=profit[j]+p[i];
    out<<profit[k];
    return 0;
}