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.