pascal
program abc;
var a,b,c:integer;
s,p:real;
begin
readln (a,b,c);
p:=(a+b+c)/2;
s:=sqrt(p*(p-a)*(p-b)*(p-c));
writeln ('s= ',s);
end.
pascal
program abc;
var a,b,c:integer;
s,p:real;
begin
readln (a,b,c);
p:=(a+b+c)/2;
s:=sqrt(p*(p-a)*(p-b)*(p-c));
writeln ('s= ',s);
end.