#include <fstream>
//DINAMICA UTILIZAND UN VECTOR
using namespace std;
ifstream fin("rucsac.in");
ofstream fout("rucsac.out");
const int NMAX= 5000;
int dp[NMAX+5];
int main()
{
    int n, k, i, j, last, g, p;
    fin>>k>>n;
    for(i=1;i<=n;++i)
        dp[i]=-1;
    last=0;
    for(i=1;i<=k;i++)
    {
        fin>>g>>p;
        for(j=last;j>=0;j--)
        {
            if(dp[j]!=-1 and j+g<=n)
            {
                dp[j+g]=max(dp[j+g], dp[j]+p);
                if(j+g>last)
                    last=j+g;
            }
        }
    }
    fout<<dp[n]<<"\n";
    return 0;
}