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: Wrong Answer)

a = list(map(int, input().split()))
count_a = 0
count_b = 0
count_c = 0
count_d = 0

for i in range(4):
    if a[i] == 1:
        count_a += 1
    if a[i] == 4:
        count_b += 1
    if a[i] == 7:
        count_c += 1
    if a[i] == 9:
        count_d += 1

if count_a == 1 and count_b == 1 and count_c == 1 and count_d == 1:
    print('Yes')
else:
    print('No')