import random

runs=10000
total=0
for i in range(runs):
    rolls=0
    w=[]
    while True:
        rolls+=1
        w.append(random.randint(1,6))
        if len(w)>6: w=w[1:]
        if w==[1,2,3,4,5,6]:
            total+=rolls
            break
    print(".", end='')
    if(i % 80 == 0):
        print("")

print(total/runs)
input()