import sys
input = sys.stdin.readline
from collections import *

N, V, C = map(int, input().split())
vw = [tuple(map(int, input().split())) for _ in range(N)]
dp1 = [0]*(V+1)

for i in range(N):
    v, w = vw[i]
    
    for j in range(V, -1, -1):
        if j-v>=0:
            dp1[j] = max(dp1[j], dp1[j-v]+w+C)

dp2 = [0]*(V+1)

for i in range(V+1):
    for v, w in vw:
        if i+v<=V:
            dp2[i+v] = max(dp2[i+v], dp2[i]+w)

ans = 0

for i in range(V+1):
    ans = max(ans, dp1[i]+dp2[V-i])

print(ans)