uses crt;

var a,b,c:integer;

   p,s:real;

begin

clrscr;

write('Nhap canh a:');readln(a);

write('Nhap canh b:');readln(b);

write('Nhap canh c:');readln(c);

p:=(a+b+c)/2;

s:=sqrt(p*(p-a)*(p-b)*(p-c));

if (a+b>c) and (b+c>a) and (a+c>b) then write(' Do la ba canh cua tam giac');

writeln('Dien tich cua tam giac la:',s:10:2)

else writeln('Do ko phai la ba canh cua tam giac');

readln;

end.