cifereka_radiko

# сам сделал без чьей-то помощи!!!
n = int(input())
n2 = 0
total_promeg = 0
total_itog = 0
total_itog2 = 0
total_promeg2 = 0
while n > 0:
    total_promeg = n % 10
    n = n // 10
    total_itog += total_promeg
#print(total_itog)
n2 = total_itog
while n2 > 0:
    total_promeg2 = n2 % 10
    n2 = n2 // 10
    total_itog2 += total_promeg2
print(total_itog2)
# другой алгоритм
n = int(input())
while n >= 10:
    total = 0
    while n > 0:
        digit = n % 10
        n = n // 10
        total += digit
    n = total
print(n)