题目描述
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".
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.
Constraints
- $0 \leq N_1, N_2, N_3, N_4 \leq 9$
- N_1, N_2, N_3 and N_4 are integers.
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
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
1 7 9 4
样例输出
YES