# Plugs

#### (OBI2013, Phase 1, Junior Level)

The International Olympiad in Informatics (IOI) is the most prestigious programming competition for high school students; its approximately 300 competitors gather every year in a different country for two days of contests. Naturally, the competitors use their free time to access the internet, program and game in their computers, but they are faced with a problem: the hotel lobby only has one plug.

Happily, the four competitors of the Brazilian team in IOI each brought a plug extension, allowing them to plug several laptops in one plug; they can also connect one extension to another and increase even more the number of available plugs. However, since each extensions has several possible plug inputs, they have asked you to write a program that, given the number of plugs in each extensions, determines the total number of plugs that could be available at the hotel lobby.

Input

The input consists of one line with four positive integers, $T_1$, $T_2$, $T_3$, $T_4$, indicating the number of plugs in each extension.

Output

Your program must output one line with an integer number, representing the maximum number of laptops that could be plugged at the same time.

Restrictions

• 2 ≤ $T_i$ ≤ 6.

Sample Input Sample Output
2 4 3 2 8
6 6 6 6 21
2 2 2 2 5