import time
a=1
b=0
c=1
d=2
print("1: 0")
while c==1:
    print(d,": ",a+b)
    a=a+b
    time.sleep(0.5)
    d=d+1
    print(d,": ",a+b)
    b=a+b
    d=d+1
    time.sleep(0.5)