스티커

n = int(input()) k = [] for b in range(n): l = [[],[]] m = int(input()) l[0] = list(map(int, input().split())) l[1] = list(map(int, input().split())) upl = [] downl = [] for i in range(m): upl += [l[i%2][i]] downl += [l[(i+1)%2][i]] if m >= 2: upl[1] += upl[0] downl[1] += downl[0] for i in range(2,m): upl[i] += max(upl[i-1],downl[i-2]) downl[i] += max(downl[i-1],upl[i-2]) k += [max(downl[-1],upl[-1])] for p in k: print(p)