n, v, c = map(int, input().split())
dp = [-10 ** 9] * (v + 1)
dp[0] = 0
for _ in range(n):
    a, b = map(int, input().split())
    for i in range(a, v + 1)[::-1]:
        dp[i] = max(dp[i], dp[i-a] + b + c)
    for i in range(a, v + 1):
        dp[i] = max(dp[i], dp[i-a] + b)
print(max(dp))