program p01;

Uses Crt;

var a,b,c,s1,S,o:real;

begin
clrscr;
repeat
writeln('Zadej strany trojuhelnika');
readln(a);readln(b);readln(c);
until (a+b>c) and (a+c>b) and (b+c>a);
o:=a+b+c;
s1:=o/2;
S:=sqrt(s1*(s1-a)*(s1-b)*(s1-c));
writeln('o=',o:5:3);
writeln('S=',S:5:3);
delay (5000);
end.