#include <bits/stdc++.h>

using namespace std;
const int N = 110;
const int INF = 0x3f3f3f3f;

int n, m;
int f[N];

int main() {
    cin >> n >> m;
    memset(f, INF, sizeof f);
    f[0] = 0;

    for (int i = 1; i <= n; i++) {
        int v, w;
        cin >> v >> w;
        for (int j = m; j >= v; j--)
            f[j] = min(f[j], f[j - v] + w);
    }
    cout << f[m] << endl;
    return 0;
}