。。水题。
直接模拟这个过程即可
arr = []
arr.append(2)
for i in range(1, 50):arr.append(1)arr.append(2 * i)arr.append(1)
up = 1
now = 99
down = arr[now]
for i in range(now - 1, -1, -1):ta = arr[i] * down + upup = downdown = ta
sum = 0
up = down
while up:sum += up % 10up /= 10
print sum