import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.io.BufferedWriter;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Shivam
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        OutputWriter out = new OutputWriter(outputStream);
        DKnapsack1Editorial solver = new DKnapsack1Editorial();
        solver.solve(1, in, out);
        out.close();
    }

    static class DKnapsack1Editorial {
        long[][] dp;

        long knapsack(int n, int w, int[] wt, int[] v) {
            if (dp[n][w] == -1) {
                if (n == 0 || w == 0)
                    dp[n][w] = 0;
                else if (wt[n] > w)
                    dp[n][w] = knapsack(n - 1, w, wt, v);
                else {
                    long v1 = knapsack(n - 1, w, wt, v);
                    long v2 = knapsack(n - 1, w - wt[n], wt, v) + v[n];
                    dp[n][w] = Math.max(v1, v2);
                }
            }
            return dp[n][w];
        }

        public void solve(int testNumber, InputReader in, OutputWriter out) {
            int n = in.nextInt();
            int w = in.nextInt();
            dp = new long[n + 1][w + 1];
            for (long[] x : dp)
                Arrays.fill(x, -1);
            int wt[] = new int[n + 1];
            int v[] = new int[n + 1];
            for (int i = 1; i <= n; i++) {
                wt[i] = in.nextInt();
                v[i] = in.nextInt();
            }
            out.println(knapsack(n, w, wt, v));
        }

    }

    static class InputReader {
        private InputStream stream;
        private byte[] buf = new byte[8192];
        private int curChar;
        private int numChars;
        private InputReader.SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (numChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= numChars) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (numChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public int nextInt() {
            int c = read();
            while (isSpaceChar(c)) {
                c = read();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }

    static class OutputWriter {
        private final PrintWriter writer;

        public OutputWriter(OutputStream outputStream) {
            writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
        }

        public OutputWriter(Writer writer) {
            this.writer = new PrintWriter(writer);
        }

        public void print(Object... objects) {
            for (int i = 0; i < objects.length; i++) {
                if (i != 0)
                    writer.print(' ');
                writer.print(objects[i]);
            }
        }

        public void println(Object... objects) {
            print(objects);
            writer.println();
        }

        public void close() {
            writer.close();
        }

    }
}



Measured memory_bytes: 139488