INF = 10 ** 9
n, v, c = map(int, input().split())
a = [0] * n
b = [0] * n
for i in range(n):
    a[i], b[i] = map(int, input().split())
dp = [-INF] * (v + 1)
dp2 = [-INF] * (v + 1)
dp[0] = 0
for i in range(n):
    for j in range(v + 1):
        if j >= a[i]:
            dp2[j] = max(dp[j], dp[j - a[i]] + b[i] + c)
        else:
            dp2[j] = dp[j]
    for j in range(v + 1):
        if j >= a[i]:
            dp2[j] = max(dp2[j], dp2[j - a[i]] + b[i])
    for j in range(v + 1):
        dp[j] = dp2[j]
print(max(dp))