import sys, time, random
from collections import deque, Counter, defaultdict
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 63 - 1
mod = 998244353

n, m, q = mi()

AB = [li() for _ in range(20)]
before = [0] * (1 << n)
for bit in range(1 << n):
    value = 0
    weight = 0
    for i in range(n):
        if 1 & (bit >> i):
            value += AB[i][1]
            weight += AB[i][0]
    if weight <= m:
        before[bit] = value
for bit in range(1 << n):
    for i in range(n):
        if (1 & (bit >> i)):
            before[bit] = max(before[bit ^ (1 << i)], before[bit])
            
after = [0] * (1 << n)

for bit in range(1 << n):
    value = 0
    weight = 0
    for i in range(n):
        if 1 & (bit >> i):
            value += AB[i][1]
            weight += AB[i][0]
    if weight <= q:
        after[bit] = value

for bit in range(1 << n):
    for i in range(n):
        if (1 & (bit >> i)):
            after[bit] = max(after[bit - (1 << i)], after[bit])
ans = 0
for bit in range(1 << n):
    ans = max(ans, before[bit] + after[(1 << n) - 1 - bit])
print(ans)