import sys

int1 = lambda x: int(x) - 1

# input = lambda: sys.stdin.buffer.readline()
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
i1 = lambda: int1(input())
mi = lambda: map(int, input().split())
mi1 = lambda: map(int1, input().split())
li = lambda: list(mi())
li1 = lambda: list(mi1())
lli = lambda n: [li() for _ in range(n)]

INF = float("inf")
mod = int(1e9 + 7)
# mod = 998244353


def chmax(arr, i, v):
    if arr[i] < v:
        arr[i] = v


n, v, c = mi()
dp = [0] * (v + 1)
for _ in range(n):
    cost, value = mi()
    nxt = dp[:]
    for i in range(v):
        if i + cost <= v:
            chmax(nxt, i + cost, dp[i] + value + c)
            chmax(nxt, i + cost, nxt[i] + value)
        chmax(nxt, i, dp[i])
    dp = nxt
print(max(dp))