#include <fstream>
#include <queue>
#include <iostream>
#include <algorithm>
using namespace std;

ifstream fin("rucsac.in");
ofstream fout("rucsac.out");
pair<int, int> v[5001];

int main()
{
    int n, s;
    fin >> n >> s;
    for (int i = 1; i <= n; i++)
        fin >> v[i].first >> v[i].second;
    bool ok = 0;
    while (!ok)
    {
        ok = 1;
        for (int i = 2; i <= n; i++)
            if (v[i - 1].second < v[i].second)
                swap(v[i - 1], v[i]),ok=0;
            else if (v[i - 1].second == v[i].second && v[i - 1].first > v[i].first)
                swap(v[i - 1], v[i]), ok = 0;
    }
    int x = 0;
    int ans = 0;
    for (int i = 1; i <= n; i++)
    {
        if (x + v[i].first <= s)
            x += v[i].first,ans+=v[i].second;
    }
    fout << ans;
    return 0;
}