* In tất cả các cặp
program bai_giai;
uses crt;
var n,i:longint;
function ktnt(k:longint):boolean;
var r:longint;
begin
ktnt:=false;
for r:=2 to trunc(sqrt(k)) do
if k mod r=0 then exit;
ktnt:=true;
end;
BEGIN
clrscr;
write('Nhap n: '); readln(n);
if n mod 2=1 then
begin
if ktnt(n-2) then write(n,' = 2+',n-2)
else write('Khong the phan tich')
end
else for i:=2 to n div 2 do
if ktnt(i) and (ktnt(n-i)) then
writeln(n,' = ',i,'+',n-i);
readln;
END.
* In cặp đầu tiên tìm thấy
program bai_giai;
uses crt;
var n,i:longint;
function ktnt(k:longint):boolean;
var r:longint;
begin
ktnt:=false;
for r:=2 to trunc(sqrt(k)) do
if k mod r=0 then exit;
ktnt:=true;
end;
BEGIN
clrscr;
write('Nhap n: '); readln(n);
if n mod 2=1 then
begin
if ktnt(n-2) then write(n,' = 2+',n-2)
else write('Khong the phan tich')
end
else for i:=2 to n div 2 do
if ktnt(i) and (ktnt(n-i)) then
begin
writeln(n,' = ',i,'+',n-i);
break;
end;
readln;
END.
