Score : 100 points
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".
Input is given from Standard Input in the following format:
N_1 N_2 N_3 N_4
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
.
1 7 9 4
YES
We can get 1974 by swapping N_2 and N_3.
1 9 7 4
YES
We already have 1974 before doing anything.
1 2 9 1
NO
4 9 0 8
NO