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.
555
555
400
200
a,b,c,d = (int(input()) for i in [0]*4)
print(min(a,b)+min(c,d))