N,V,C = map(int,input().split())
INF = float('inf')
dp = [-INF] * (V+1)
dp[0] = 0
for _ in range(N):
    ndp = [-INF] * (V+1)
    vi,wi = map(int,input().split())
    for v  in range(V+1):
        if v - vi >= 0:
            ndp[v] = max(dp[v-vi] + C+wi,ndp[v-vi] + wi,ndp[v])
        ndp[v] = max(dp[v],ndp[v])
    dp = ndp
print(max(ndp))