N = int(input())
A = list(map(int, input().split()))
B = list(map(int, input().split()))
C = list(map(int, input().split()))

D = [B[i] - A[i] for i in range(N)]
E = [C[i] - B[i] for i in range(N)]

ans = sum(A)

P = [0]
for i in D:
	P.append(P[-1] + i)

Q = [0]
for i in E:
	Q.append(Q[-1] + i)

K = [0]
M = 0
for i in range(1, N + 1):
	M = min(M, P[i])
	K.append(min(K[-1], M + Q[i]))

L = [0] * (N + 1)
L[N] = P[N] + Q[N]
M = P[N]
for i in range(N - 1, -1, -1):
	M = max(M, P[i])
	L[i] = max(L[i + 1], M + Q[i])

ans = max(ans, sum(A) + max(L[i + 1] - K[i] for i in range(N)))

X = [0]
M = 0
for i in range(1, N + 1):
	M = min(M, P[i])
	X.append(max(X[-1], P[i] - M))

Y = [0] * (N + 1)
Y[N] = 0
M = P[N]
for i in range(N - 1, -1, -1):
	M = max(M, P[i])
	Y[i] = max(Y[i + 1], M - P[i])

ans = max(ans, sum(A) + max(X[i] + Y[i + 1] for i in range(N)))

ans = max(ans, sum(A) + max(X))

print(ans)