goalx, goaly = map(int, raw_input().split())
pawnx, pawny = map(int, raw_input().split())

if goalx == pawnx == 0 or goaly == pawny == 0:
    ans = goalx + goaly + 2

elif goalx == goaly and pawnx == pawny:
    ans = goalx + 1

else:
    ans = goalx + goaly - min(goalx, goaly)

print ans