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

            tmp = (V-ii)//vs[i] #買える個数

            for iii in range(tmp,0,-1):
                tmp2 = ii+(iii*vs[i])
                dp[i+1][tmp2] = max(dp[i+1][tmp2],dp[i][ii]+(ws[i]*iii+C))

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

print(ans)