import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################

n,V,c = na()
w,v = zip(*[na() for i in range(n)])

dp = [0 for i in range(V+1)]
for i in range(n):

    for j in range(V+1):
        if j + w[i] <= V:
            dp[j+w[i]] = max(dp[j+w[i]], dp[j] + v[i])
    for j in range(V,-1,-1):
        if j + w[i] <= V:
            dp[j+w[i]] = max(dp[j+w[i]], dp[j] + c + v[i])

    #print(dp)
print(dp[-1])