#include<fstream>

using namespace std;

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

const int N = 5001;

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

int main()
{
	int i,j,n,k;
	v[0]=0;
	in>>n>>k;
	for(j=1;j<=n;j++)
		in>>g[j]>>p[j];
	v[0]=0;
	for(j=1;j<=k;j++)
		v[j]=-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';
	return 0;
}