#besme taala
#ya_hossein
from types import GeneratorType
def bootstrap(f, stack=[]):
    def wrappedfunc(*args, **kwargs):
        if stack:
            return f(*args, **kwargs)
        else:
            to = f(*args, **kwargs)
            while True:
                if type(to) is GeneratorType:
                    stack.append(to)
                    to = next(to)
                else:
                    stack.pop()
                    if not stack:
                        break
                    to = stack[-1].send(to)
            return to
    return wrappedfunc
n = int(input())
num1 = list(map(int, input().split()))
num0 = list(map(int, input().split()))
arr1 = (n + 1)*[0]
arr0 = (n + 1)*[0]
@bootstrap
def ans1(x):
    if x >= n:
        yield 0
    if arr1[x]:
        yield arr1[x]
    arr1[x] = num1[x] + max((ans0(x + 1)), ans0(x + 2))
    yield arr1[x]
@bootstrap
def ans0(x):
    if x >= n:
        yield 0
    if arr0[x]:
        yield arr0[x]
    arr0[x] = num0[x] + max(ans1(x + 1), ans1(x + 2))
    yield arr0[x]
print(max(ans0(0), ans1(0)))