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

INF = 10**18
dp = [-INF]*(V+1)
dp[0] = 0

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

print(max(dp))