#include <bits/stdc++.h>

using namespace std;
const int N = 1010;
int n, m;
int w[N], v[N];
int res;

void dfs(int u, int r, int s) {
    if (u == n + 1) {
        res = max(res, s);
        return;
    }
    if (v[u] <= r) dfs(u + 1, r - v[u], s + w[u]);
    dfs(u + 1, r, s);
}

int main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++) cin >> v[i] >> w[i];
    dfs(1, m, 0);
    printf("%d\n", res);
    return 0;
}