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 Pascal (FPC 3.0.4) (judge verdict: Accepted)

var a:array[1..4] of integer;n1,n2,n3,n4,s,tmp,i,j:integer;
begin
for i:=1 to 4 do begin
read(a[i]);
end;
for i:=1 to 3 do begin
if(a[i]>a[i+1])then begin
j:=i+1;
while(j>1)do begin
if(a[j-1]>a[j])then begin
tmp:=a[j];
a[j]:=a[j-1];
a[j-1]:=tmp;
end;
j:=j-1;
end;
end;
end;
s:=1000*a[1]+100*a[2]+10*a[3]+a[4];
if(s=1479)then writeln('YES') else writeln('NO');
end.