You planned a trip using trains and buses. The train fare will be A yen (the currency of Japan) if you buy ordinary tickets along the way, and B yen if you buy an unlimited ticket. Similarly, the bus fare will be C yen if you buy ordinary tickets along the way, and D yen if you buy an unlimited ticket.  Find the minimum total fare when the optimal choices are made for trains and buses.
a = int(input())
a = int(input())
a = int(input())
b = int(input())
c = int(input())
d = int(input())
print(min(a, b) + min(c, d))