import sys
import pypyjit
import itertools
import heapq
import math
from collections import deque, defaultdict, Counter
import string
import random

input = sys.stdin.readline
sys.setrecursionlimit(10 ** 6)
pypyjit.set_param('max_unroll_recursion=-1')


N, Pmax, C = map(int, input().split())
P = [tuple(map(int, input().split())) for _ in range(N)]

dp = [[0 for _ in range(Pmax + 1)] for _ in range(2 * N + 1)]
for i in range(N):
    price, value = P[i]
    value += C
    for j in range(Pmax + 1):
        if j + price <= Pmax:
            dp[i + 1][j + price] = max(dp[i + 1][j + price], dp[i][j] + value)
        dp[i + 1][j] = max(dp[i + 1][j], dp[i][j])
for i in range(N):
    price, value = P[i]
    for j in range(Pmax + 1):
        if j + price <= Pmax:
            dp[N + i + 1][j + price] = max(dp[N + i + 1][j + price], dp[N + i][j] + value, dp[N + i + 1][j] + value)
        dp[N + i + 1][j] = max(dp[N + i + 1][j], dp[N + i][j])
print(max(dp[2 * N]))