def Area_Perimeter(a,b,ch=1):
    """
        a(int): Length of the rectangle
        b(int): Breadth of the rectangle
        ch(int): choice
                ch==1>>Area
                ch==2>>Perimeter
        Returns area or perimeter of the rectangle.
    """
    if ch==1:
        return 'Area is '+str(a*b)
    elif ch==2:
        return 'Perimeter is '+str(2*(a+b))
    else:
        return 'Invalid choice.'