import sys
input = sys.stdin.readline
N = int(input())
A = list(map(int, input().split()))
B = list(map(int, input().split()))
C = list(map(int, input().split()))
V = [A, B, C]
dp = [[[-1 for _ in range(3)] for _ in range(3)] for _ in range(N+1)]
dp[0][0][0] = 0
for i in range(N):
    for j in range(3):
        for k in range(3):
            if dp[i][j][k]==-1:
                continue
            if k==0:
                dp[i+1][j][k] = max(dp[i+1][j][k], dp[i][j][k]+V[j][i])
                dp[i+1][j+1][k+1] = max(dp[i+1][j+1][k+1], dp[i][j][k]+V[j+1][i])
                dp[i+1][j+2][k+2] = max(dp[i+1][j+2][k+2], dp[i][j][k]+V[j+2][i])
            elif k==1:
                dp[i+1][j][k] = max(dp[i+1][j][k], dp[i][j][k]+V[j][i])
                dp[i+1][j+1][k+1] = max(dp[i+1][j+1][k+1], dp[i][j][k]+V[j+1][i])
                if j-1>=0:
                    dp[i+1][j-1][k] = max(dp[i+1][j-1][k], dp[i][j][k]+V[j-1][i])
            else:
                dp[i+1][j][k] = max(dp[i+1][j][k], dp[i][j][k]+V[j][i])
                if j-1>=0:
                    dp[i+1][j-1][k] = max(dp[i+1][j-1][k], dp[i][j][k]+V[j-1][i])
                if j-2>=0:
                    dp[i+1][j-2][k] = max(dp[i+1][j-2][k], dp[i][j][k]+V[j-2][i])
ans = 0
for j in range(3):
    for k in range(3):
        ans = max(ans, dp[N][j][k])
print(ans)