digital_root.py

import math
def digitalRoot(num):
	if (num == "0"):
		return 0
	ans = 0
	for i in range (0, len(num)):
		ans = (ans + int(num[i])) % 9
	if(ans == 0):
		return 9
	else:
		return ans % 9
num = int(input())
print (digitalRoot(num))