#include <bits/stdc++.h>
using namespace std;

// A utility function that returns
// maximum of two integers
int max(int a, int b) { return (a > b) ? a : b; }

// Returns the maximum value that
// can be put in a knapsack of capacity W
int knapSack(int W, int wt[], int val[], int n)
{

    // Base Case
    if (n == 0 || W == 0)
        return 0;

    // If weight of the nth item is more
    // than Knapsack capacity W, then
    // this item cannot be included
    // in the optimal solution
    if (wt[n - 1] > W)
        return knapSack(W, wt, val, n - 1);

    // Return the maximum of two cases:
    // (1) nth item included
    // (2) not included
    else
        return max(val[n - 1] + knapSack(W - wt[n - 1],wt, val, n - 1),knapSack(W, wt, val, n - 1));
}

// Driver code
int n, W, val[1002], wt[1002];
int main()
{

    freopen("energii.in", "r", stdin);
    freopen("energii.out", "w", stdout);

    scanf("%d %d",&n,&W);
    for(int i = 0;i < n; i++) {
        scanf("%d %d",&wt[i],&val[i]);
    }
    cout << knapSack(W, wt, val, n);
    return 0;
}