n,V,c = map(int,input().split())

vw = [list(map(int,input().split())) for _ in range(n)]
dp = [-1] * (V+1)
dp[0] = 0
for v,w in vw:
    n_dp = [-1] * (V+1)
    for i in range(V+1):
        if dp[i] >= 0:
            if i + v <= V:
                n_dp[i+v] = max(n_dp[i+v],dp[i] + w+c)
    for i in range(V+1):
        if n_dp[i] >= 0:
            if i + v <= V:
                n_dp[i+v] = max(n_dp[i+v],n_dp[i] + w)
    
    for i in range(V+1):
        n_dp[i] = max(dp[i],n_dp[i])
#     print(n_dp)
    dp = n_dp[::]
print(max(dp))