#!/usr/bin/env PyPy3

from collections import Counter, defaultdict, deque
import itertools
import re
import math
from functools import reduce
import operator
import bisect
from heapq import *
import functools
mod=998244353

import sys
input=sys.stdin.readline
n,V,c=map(int,input().split())
INF = 1 << 31
dp = [-INF] * (V+1)
dp[0] = 0
for i in range(n):
    v,w=map(int,input().split())
    for j in range(v,V+1):
        dp[j] = max(dp[j],dp[j-v]+w)
    for j in range(v,V+1)[::-1]:
        dp[j] = max(dp[j],dp[j-v]+w+c)
print(max(dp))