program while22;
uses crt;
var
n,i,j,k:longint;
f:boolean;
begin
clrscr;
repeat
write('Введите число ');
readln(n);
until n > 0;
if n < 2 then
f:=false
else
begin
f:=true;
j:=2;
while (j <= round(sqrt(n))) and f do
begin
if n mod j=0 then
f:=false
else
j:=j+1;
end;
end;
write(f);
readln
end.