import sys
input = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 7)
inf = 10 ** 10

N, V, C = map(int, input().split())
dp = [-inf] * (V + 1)
dp[0] = 0
for _ in range(N):
    v, w = map(int, input().split())
    memo = set()
    for i in range(v, V+1):
        if i - v in memo:
            if dp[i] < dp[i-v] + w:
                memo.add(i)
                dp[i] = dp[i-v] + w
        else:
            if dp[i] < dp[i-v] + w + C:
                memo.add(i)
                dp[i] = dp[i-v] + w + C

print(max(dp))