program perimeter;
var a, b:real;
begin
write('введите сторону: ');
read(a);
b:=a*4;
write('периметр = ',b);
end.
program perimeter;
var a, b:real;
begin
write('введите сторону: ');
read(a);
b:=a*4;
write('периметр = ',b);
end.