#include <fstream>
#define mini(a, b) ( (a)<(b) ? (a) : (b) )

using namespace std;
ifstream cin ("energii.in");
ofstream cout ("energii.out");

const int MAX = 5e3 + 5;

int n, caut, val, g, v[MAX], rez = MAX;

int main()
{
    cin>>n>>caut;
    for(int i=1; i<=n; ++i)
    {
        cin>>g>>val;
        for(int j=g; j>=0; --j)
            if(v[j+g]<v[j]+val){
                v[j+g]=v[j]+val;
                if(v[j+g] >= caut){
                    rez = mini(rez, v[j+g]);
                }
            }
    }
    cout<<rez;
    return 0;
}