program r7_38;
uses crt;
const n=20;
var a,b:array[1..n] of integer;
i,j,r,r1,d:integer;
h:boolean;
function Simple(x:word):boolean;
var d:word;
begin
d:=2;
while(x mod d <>0) and(d<=sqrt(x))do
d:=d+1;
simple:=(d>sqrt(x));
end;
Begin
clrscr;
randomize;
for i:=1 to n do begin
a[i]:=random(50);
write(a[i]:4);
end;writeln;
h:=false;
for i:=1 to n-1 do
for j:=i+1 to n do
if ((abs(a[i]-a[j])=2) and simple(a[i]) and simple(a[j]))then
begin
h:=true;
r:=a[i];
r1:=a[j];
end;
if h=true then writeln('est:',r:4,' ',r1:4)
else writeln('net');
END.