import sys

# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()
dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = (1 << 63)-1
# inf = (1 << 31)-1
md = 10**9+7
# md = 998244353

n, V, c = LI()

dp = [[0]*(n+1) for _ in range(V+1)]
mx = [[0]*(n+1) for _ in range(V+1)]
vw = LLI(n)

for i in range(1, V+1):
    for j, (v, w) in enumerate(vw,1):
        if i-v < 0: continue
        dp[i][j] = dp[i-v][j]+w
        if j:
            dp[i][j] = max(dp[i][j], mx[i-v][j-1]+w+c)
            mx[i][j] = max(dp[i][j], mx[i][j-1])
        else:
            mx[i][j] = dp[i][j]
# p2D(dp)
# p2D(mx)

ans = mx[-1][-1]
print(ans)