var
a, b, buf:real;
begin
write('a = '); readln(a);
write('b = '); readln(b);
buf := a;
a := b;
b := buf;
writeln('a = ', a);
writeln('b = ', b);
end.
// без буферной переменной
var
a, b:real;
begin
write('a = '); readln(a);
write('b = '); readln(b);
a := a + b;
b := a - b;
a := a - b;
writeln('a = ', a);
writeln('b = ', b);
end.