import sys

# sys.setrecursionlimit(1000005)
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()
vw=LLI(n)

dp=[0]*(V+1)
for v,w in vw:
    for i in range(V-v,-1,-1):
        dp[i+v]=max(dp[i+v],dp[i]+w+c)

dq=[0]*(V+1)
for i in range(V):
    for v,w in vw:
        if i+1-v>=0:dq[i+1]=max(dq[i+1],dq[i+1-v]+w)

ans=0
for i in range(V+1):
    ans=max(ans,dp[i]+dq[V-i])

print(ans)