#Power digit sum
#Problem 16
#
#215 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26.
#
#What is the sum of the digits of the number 21000?


pp = 1000

c = [0 for i in range(0, pp//3+1)]
c[0] = 1

for i in range(0,pp):
    r = 0
    for j in range(0,len(c)):
        p = c[j]*2+r
        r = p//10
        c[j] = p%10

print( sum(c) )