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"""
2^15 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26.
What is the sum of the digits of the number 2^1000?
"""
def solution(power):
"""Returns the sum of the digits of the number 2^power.
>>> solution(1000)
1366
>>> solution(50)
76
>>> solution(20)
31
>>> solution(15)
26
"""
n = 2 ** power
r = 0
while n:
r, n = r + n % 10, n // 10
return r
if __name__ == "__main__":
print(solution(int(str(input()).strip())))