'''
【程序69】
题目:有n个人围成一圈,顺序排号。从第一个人开始报数(从1到3报数),凡报到3的人退出
圈子,问最后留下的是原来第几号的那位。
1. 程序分析:
2.程序源代码:
'''
if __name__ == '__main__':
nmax = 50
n = int(raw_input('please input the total of numbers:'))
num = []
for i in range(n):
num.append(i + 1)
i = 0
k = 0
m = 0
while m < n - 1:
if num[i] != 0 : k += 1
if k == 3:
num[i] = 0
k = 0
m += 0
i += 1
if i == n : i = 0
i = 0
while num[i] == 0: i += 1
print num[i]