program fs;
label 1;
var
s: string;
a: integer;
code: integer;
begin
1:
write('Vvedite cislo: ');
readln(s);
val(s, a, code);
if code <> 0 then
begin
writeln('Vy vveli nevernoe cislo');
goto 1;
end;
if a < 0 then
begin
writeln('Vy vveli OTRICATELINOE cislo');
goto 1;
end;
writeln('SQRT= ', sqrt(a):0:2);
readln;
end.