Problem:
Score : 100 points

Problem Statement

You are given four digits N_1, N_2, N_3 and N_4. Determine if these can be arranged into the sequence of digits "1974".

Constraints

0 \leq N_1, N_2, N_3, N_4 \leq 9

N_1, N_2, N_3 and N_4 are integers.

Input

Input is given from Standard Input in the following format:

N_1 N_2 N_3 N_4

Output

If N_1, N_2, N_3 and N_4 can be arranged into the sequence of digits "1974", print YES; if they cannot, print NO.

Sample Input 1

1 7 9 4

Sample Output 1

YES

We can get 1974 by swapping N_2 and N_3.

Sample Input 2

1 9 7 4

Sample Output 2

YES

We already have 1974 before doing anything.

Sample Input 3

1 2 9 1

Sample Output 3

NO

Sample Input 4

4 9 0 8

Sample Output 4

NO

Solution in Ruby (2.3.3) (judge verdict: Accepted)

i =  gets.chomp.split(" ").map(&:to_i)
one, nine, seven, four = false
i.each do |hoge|
    one = true if hoge == 1 
    nine = true if hoge == 9
    seven = true if hoge == 7
    four = true if hoge == 4
end
if one and nine and seven and four then
    puts "YES"
else
    puts "NO"
end