#include <fstream>

using namespace std;

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

int gr[5001];
int pr[5001];

int dp[10001][3];

int main()
{
    int n, g;
    cin >> n >> g;
    for (int i = 1; i <= n; i ++)
    {
        cin >> gr[i] >> pr[i];
    }
    for (int j = 1; j <= n; j ++)
    {
        for (int i = 1; i <= g; i ++)
        {
            dp[i][1] = dp[i][2];
            dp[i][2] = max(dp[i][1], i >= gr[j] ? dp[i - gr[j]][1] + pr[j] : -1);
        }
    }
    cout << dp[g][2];
    return 0;
}