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 Python (3.4.3) (judge verdict: Accepted)

a, b, c, d = map(int, input().split())

if a==1 or a==9 or a==7 or a==4:
	if b==1 or b==9 or b==7 or b==4:
			if c==1 or c==9 or c==7 or c==4:
					if d==1 or d==9 or d==7 or d==4:
						s = a+b+c+d
						if s==21:
							print('YES')
						else:
							print('NO')
					else:
						print('NO')
			else:
				print('NO')
	else:
		print('NO')
else:
	print('NO')