# power2.py
def power2(n):
    if n<=0:
      return 1
    f=2
    while n>1:
      f=f*2
      n=n-1
    return f
print "2^0=",
print power2(0)
print "2^1=",
print power2(1)
print "2^2=",
print power2(2)
print "2^3=",
print power2(3)
print "2^100=",
print power2(100)
print "2^200=",
print power2(200)
print "2^200+0.1=",
print power2(200)+0.1
print "1.2e154*1.2e154=",
print 1.2e154*1.2e154
print "1.2e155*1.2e155=",
print 1.2e155*1.2e155