Problem:
Score : 400 points

Problem Statement

You have N items and a bag of strength W.
The i-th item has a weight of w_i and a value of v_i.

You will select some of the items and put them in the bag.
Here, the total weight of the selected items needs to be at most W.

Your objective is to maximize the total value of the selected items.

Constraints

1 ≤ N ≤ 100

1 ≤ W ≤ 10^9

1 ≤ w_i ≤ 10^9

For each i = 2,3,...,N, w_1 ≤ w_i ≤ w_1 + 3.

1 ≤ v_i ≤ 10^7

W, each w_i and v_i are integers.

Input

Input is given from Standard Input in the following format:

N W
w_1 v_1
w_2 v_2
:
w_N v_N

Output

Print the maximum possible total value of the selected items.

Sample Input 1

4 6
2 1
3 4
4 10
3 4

Sample Output 1

11

The first and third items should be selected.

Sample Input 2

4 6
2 1
3 7
4 10
3 6

Sample Output 2

13

The second and fourth items should be selected.

Sample Input 3

4 10
1 100
1 100
1 100
1 100

Sample Output 3

400

You can take everything.

Sample Input 4

4 1
10 100
10 100
10 100
10 100

Sample Output 4

0

You can take nothing.

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;

public class Main {

	public static void main(String args[]) {
		FastScanner cin = new FastScanner();
		PrintWriter cout = new PrintWriter(System.out);
		solve(cin, cout);
		cout.flush();
	}

	private static void solve(FastScanner cin, PrintWriter cout) {
		assert solve(4, 6, new int[][] { { 2, 1 }, { 3, 4 }, { 4, 10 }, { 3, 4 } }) == 11;
		assert solve(4, 10, new int[][] { { 1, 100 }, { 1, 100 }, { 1, 100 }, { 1, 100 } }) == 400;
		assert solve(4, 1, new int[][] { { 10, 100 }, { 10, 100 }, { 10, 100 }, { 10, 100 } }) == 0;
		int N = cin.nextInt();
		int W = cin.nextInt();
		int[][] wv = new int[N][];
		for (int i = 0; i < N; i++)
			wv[i] = new int[] { cin.nextInt(), cin.nextInt() };
		long ans = solve(N, W, wv);
		cout.println(ans);
	}

	private static long solve(long N, long W, int[][] wv) {
		// Q.メモリ使用量／計算量が爆発しないか？
		// A. w[1]<=w[i]<=w[1]+3, for i=2..N
		HashMap<Integer, Long> valueByWeight = new HashMap<>();
		valueByWeight.put(0, 0L);
		HashMap<Integer, Long> temp = new HashMap<>();
		for (int[] z : wv) {
			int w = z[0];
			int v = z[1];
			temp.clear();
			temp.putAll(valueByWeight);
			for (Map.Entry<Integer, Long> entry : valueByWeight.entrySet()) {
				int nw = entry.getKey() + w;
				long nv = entry.getValue() + v;
				if (nw > W)
					continue;
				if (temp.containsKey(nw) && temp.get(nw) > nv)
					continue;
				temp.put(nw, nv);
			}
			HashMap<Integer, Long> sw = temp;
			temp = valueByWeight;
			valueByWeight = sw;
			// System.out.println(sw);
		}
		long ans = valueByWeight.values().stream().mapToLong(x -> x).max().getAsLong();
		return ans;
	}

	/**
	 * How to read input in Java — tutorial <br />
	 * By Flatfoot<br />
	 * http://codeforces.com/blog/entry/7018
	 */
	static class FastScanner {
		private BufferedReader br;
		private StringTokenizer st;

		FastScanner() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreElements())
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					throw new IllegalStateException(e);
				}
			return st.nextToken();
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (IOException e) {
				throw new IllegalStateException(e);
			}
			return str;
		}

		long nextLong() {
			return Long.parseLong(next());
		}
	}

}