#include<fstream>
using namespace std;
int n, w, i, j, minim, x;
int f[20002], c[20002];
pair<int, int> v[1001];
ifstream fin("energii.in");
ofstream fout("energii.out");
int main(){
    fin>> n >> w;
    for(i = 1; i <= n; i++){
        fin>> v[i].first >> v[i].second;
    }
    for(i = 1; i <= 20000; i++){
        c[i] = 1000000000;
    }
    minim = 1000000000;
    f[0] = 1;
    c[0] = 0;
    for(i = 1; i <=  n; i++){
        for(j = w - 1; j >= 0; j--){
            if(f[j] == 1){
                x = j + v[i].first;
                f[x] = 1;
                c[x] = c[j] + v[i].second;
            }
        }
    }
    for(i = w; i <= 20000; i++){
        minim = min(minim, c[i]);
    }
    fout<< minim <<"\n";
    return 0;
}