import java.io.*;
import java.util.*;

public class Main {
    static int c;
    static int[] costs;
    static int[] values;
    static int[][][] dp;
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int v = sc.nextInt();
        c = sc.nextInt();
        costs = new int[n];
        values = new int[n];
        for (int i = 0; i < n; i++) {
            costs[i] = sc.nextInt();
            values[i] = sc.nextInt();
        }
        dp = new int[2][n][v + 1];
        for (int[][] arr1 : dp) {
            for (int[] arr2 : arr1) {
                Arrays.fill(arr2, -1);
            }
        }
        System.out.println(dfw(0, n - 1, v));
    }
    
    static int dfw(int times, int idx, int v) {
        if (v < 0) {
            return Integer.MIN_VALUE;
        }
        if (idx < 0) {
            return 0;
        }
        if (dp[times][idx][v] < 0) {
            dp[times][idx][v] = dfw(0, idx - 1, v);
            int add = 0;
            if (times == 0) {
                add = c;
            }
            dp[times][idx][v] = Math.max(dp[times][idx][v], Math.max(dfw(0, idx - 1, v - costs[idx]) + add + values[idx], dfw(1, idx, v - costs[idx]) + add + values[idx]));
        }
        return dp[times][idx][v];
    }
}

class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}