#include <iostream>
#include <vector>

using namespace std;

int main() {
    int N, W;
    cin >> N >> W;

    vector<int> v(N), w(N);

    for (int i = 0; i < N; ++i) {
        cin >> v[i] >> w[i];
    }

    vector<vector<int>> dp(N + 1, vector<int>(W + 1, 0));

    for (int i = 1; i <= N; ++i) {
        for (int weight = 1; weight <= W; ++weight) {
            if (w[i - 1] <= weight) {
                dp[i][weight] = max(dp[i - 1][weight], dp[i - 1][weight - w[i - 1]] + v[i - 1]);
            } else {
                dp[i][weight] = dp[i - 1][weight];
            }
        }
    }

    int maxCapacity = dp[N][W];

    if (maxCapacity == 0) {
        cout << "-1" << endl;  // Knapsack not possible
    } else {
        cout << maxCapacity << endl;
    }

    return 0;
}