import sys,random,bisect
from collections import deque,defaultdict
import heapq
from itertools import permutations
from math import gcd

input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

INF = 10**17

N,V,C = mi()
dp = [-INF] * (V+1)
dp[0] = 0

for _ in range(N):
    v,w = mi()
    ndp = [-INF] * (V+1)
    for i in range(V+1-v):
        ndp[i+v] = dp[i]+C+w
    for i in range(V+1):
        ndp[i] = max(dp[i],ndp[i])
        if v <= i:
            ndp[i] = max(ndp[i],ndp[i-v]+w)
    dp = ndp

print(max(dp))