#include <iostream>
#include <vector>
#include <map>
#include <cstring>
#include <fstream>
#include <sstream>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
#include <unordered_map>
#include <stack>
#include <iomanip>
#include <random>

using namespace std;

ifstream fin("rucsac.in");
ofstream fout("rucsac.out");

int n, maxWeight;
int maxProfit = -1;
vector<pair<int, int>> backpack;

void backtracking(int sumWeight, int sumProfit, int start) {
    if (sumWeight > maxWeight) {
        return;
    }

    maxProfit = max(maxProfit, sumProfit);

    for (int i = start; i < backpack.size(); ++i) {
        backtracking(sumWeight + backpack[i].first, sumProfit + backpack[i].second, i + 1);
    }
}

int main() {
    fin >> n >> maxWeight;

    for (int i = 0; i < n; ++i) {
        int weight, profit;
        fin >> weight >> profit;
        backpack.emplace_back(weight, profit);
    }
    
    backtracking(0, 0, 0);

    fout << maxProfit;

    return 0;
}