n, v, c = map(int, input().split())
dp = [0] * (v + 1)
for _ in range(n):
    vi, wi = map(int, input().split())
    dp2 = [0] * (v + 1)
    for i in range(v + 1):
        if i + vi <= v:
            dp2[i + vi] = max(dp[i] + c, dp2[i]) + wi
        dp[i] = max(dp[i], dp2[i])
print(dp[v])