uses crt;
var a,b,c:longint; p:real;
begin
clrscr;
write('Nhap 3 canh cua tam giac: ');readln(a,b,c);
if (a+b>c)and(a+c>b)and(b+c>a) then
begin
writeln('Day la ba canh cua tam giac');
if (a=b)or(b=c)or(a=c) then writeln('Day la tam giac can');
if (a=b)and(b=c) then writeln('Day la tam giac deu');
if (sqr(a)+sqr(b)=sqr(c))or(sqr(a)+sqr(c)=sqr(b))or(sqr(b)+sqr(c)=sqr(a))
then writeln('Day la tam giac vuong');
p:=(a+b+c)/2;
writeln('Chu vi: ',a+b+c);
writeln('Dien tich: ',sqrt(p*(p-a)*(p-b)*(p-c)));
end else writeln('Day khong la ba canh cua tam giac');
readln
end.