program p17;
Uses Crt;
var o1,o2,prep:real;

begin
clrscr;
repeat
  write('Zadej delku 1. odvesny : ');readln(o1);
until o1>=0;
repeat
  write('Zadej delku 2. odvesny : ');readln(o2);
until (o2>0) or ((o2=0) and (o1>0));
repeat
  write('Zadej delku prepony : ');readln(prep);
until ((prep>o1) and (prep>o2)) or ((prep=0) and (o1>0) and (o2>0));
if (o1>0) and (o2>0) and (prep>0) then
  begin
  if prep*prep=o1*o1+o2*o2 then writeln('Trojuhelnik je pravouhly.')
                           else writeln('Trojuhelnik neni pravouhly.');
  end
else
  begin
  if o1=0 then writeln('Prvni odvesna ma delku ',sqrt(prep*prep-o2*o2):5:2);
  if o2=0 then writeln('Druha odvesna ma delku ',sqrt(prep*prep-o1*o1):5:2);
  if prep=0 then writeln('Prepona ma delku ',sqrt(o1*o1+o2*o2):5:2);
  end;
repeat until keypressed;
end.