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)

a = gets.split(" ").map!{|i| i.to_i}
n1 = 0
n2 = 0
n3 = 0
n4 = 0
4.times do |i|
  if a[i] == 1 then n1 += 1
  elsif a[i] == 7 then n2 += 1
  elsif a[i] == 9 then n3 += 1
  elsif a[i] == 4 then n4 += 1
  end
end
if n1 == 1 and n2 == 1 and n3 == 1 and n4 == 1 
  puts "YES"
else puts "NO"
end