Score : 100 points

Problem Statement

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.

Constraints

  • 1 \leq A \leq 1 000
  • 1 \leq B \leq 1 000
  • 1 \leq C \leq 1 000
  • 1 \leq D \leq 1 000
  • All input values are integers.

Input

Input is given from Standard Input in the following format:

A
B
C
D

Output

Print the minimum total fare.


Sample Input 1

600
300
220
420

Sample Output 1

520

The train fare will be 600 yen if you buy ordinary tickets, and 300 yen if you buy an unlimited ticket. Thus, the optimal choice for trains is to buy an unlimited ticket for 300 yen. On the other hand, the optimal choice for buses is to buy ordinary tickets for 220 yen.

Therefore, the minimum total fare is 300 + 220 = 520 yen.


Sample Input 2

555
555
400
200

Sample Output 2

755

Sample Input 3

549
817
715
603

Sample Output 3

1152