Var
a, b: real;
begin
readln(a, b);
writeln(P = , 2 * (a + b));
writeln(S = , a * b);
end.
2)
var
a, b, c: real;
begin
readln(a, b, c);
writeln(cos(alpha) = , (b * b + c * c - a * a) / (2 * b * c));
writeln(cos(beta) = , (a * a + c * c - b * b) / (2 * a * c));
writeln(cos(gamma) = , (a * a + b * b - c * c) / (2 * a * b));
end.