import sys
input = lambda: sys.stdin.readline().rstrip()

#  -----------------------  #

n, V, C = map(int, input().split())
vw = [list(map(int, input().split())) for _ in range(n)]

dp = [[0]*(V+1) for _ in range(n+1)]
dp[0][0] = 0

for i in range(n):
  v, w = vw[i]
  for j in range(V+1):
    dp[i+1][j] = max(dp[i+1][j], dp[i][j])

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

print(max(dp[n]))