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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <sstream>
#include <algorithm>
#include <vector>
#include <string>

using namespace std;

int main(void) {
  vector<int> num;

  for(int i=0; i<4; i++) {
    int tmp;
    cin >> tmp;
    num.push_back(tmp);
  }

  sort(num.begin(), num.end());

  string str = "";
  for (int i=0; i<4; i++) {
    str += to_string(num[i]);
  }

  if(str == "1479"){
    cout << "YES" << endl;
  } else {
    cout << "NO" << endl;
  }

  return 0;

}