#include <iostream>
#include <fstream>
#include <queue>
#include <vector>
using namespace std;
ifstream fin("energii.in");
ofstream fout("energii.out");

const int LMAX = 100005;

int main() {
    int n, e, x, y, i, j;
    fin>>n>>e;
    vector<int> dp(e + 1, -1); //dp[i] costul minim pentru generatoare care au puterea i
    dp[0] = 0;
    for (i = 0; i < n; i++) {
        fin>>x>>y;
        for (j = e; j >= 0; j--) {
            if (dp[j] != -1) {
                int s = j + x;
                if (s > e) s = e;
                if (dp[s] == -1 || dp[s] > dp[j] + y)
                    dp[s] = dp[j] + y;
            }
        }
    }
    fout<<dp[e];



    fin.close();
    fout.close();
    return 0;
}