#include <fstream>

using namespace std;

ifstream in ("rucsac.in");
ofstream out ("rucsac.out");

const int N = 5002;
int profit[N], v[N], x[N];

int main()
{
    int n, k, maxi = -2;
    in >> n >> k;
    for (int i = 0; i < n; i++)
    {
        in >> v[i] >> x[i];
    }
    profit[0] = 0;
    for (int j = 1; j <= k; j++)
    {
        profit[j] = -1;
    }
    for (int i = 0; i < n; i++)
    {
        for (int j = k - v[i]; j >= 0; j--)
        {
            if ((profit[j] != -1) && (profit[j] + x[i] > profit[j+ v[i]]))
            {
                profit[j + v[i]] = profit[j] + x[i];
            }
        }
    }
    for (int j = 1; j <= k; j++)
    {
        maxi = max(maxi, profit[j]);
    }
    out << maxi;
    return 0;
}