uses crt;

var a,b,c,s:real;

begin

clrscr;

textcolor(14);

writeln('a=');

readln(a);

writeln('b=');

readln(b);

writeln('c=');

readln(c);

s:=(a*b+b*c+c*a)*2;

writeln('s:=(a*b+b*c+c*a)2=',s:2:2);

readln;

end.