N,V,C = map(int,input().split())

vs = [] #値段
ws = [] #価値

for i in range(N):
    v,w = map(int,input().split())
    vs.append(v)
    ws.append(w)

dp = []  #購入したものの価値総計

for i in range(N+1):
    dp.append([-1]*(V+1))

dp[0][0] = 0

for i in range(1,N+1):
    tmp = []

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

        if  ii-vs[i-1] >= 0 and dp[i-1][ii-vs[i-1]]!=-1:
            if dp[i][ii] < dp[i-1][ii-vs[i-1]]+ws[i-1]+C:
                dp[i][ii] = dp[i-1][ii-vs[i-1]]+ws[i-1]+C
                dp[i-1][ii] = max(dp[i-1][ii],dp[i-1][ii-vs[i-1]]+ws[i-1])

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

print(ans)