x=10
y=20
print(" Before {:3d} and {:3d} ".format(x,y))
x,y=y,x
print(" After  {:3d} and {:3d} ".format(x,y))
x1=1.0
x2=2.0
print(" Before {:4.1f} and {:4.1f} ".format(x1,x2))
x1,x2=x2,x1
print(" After  {:4.1f} and {:4.1f} ".format(x1,x2))