2231

n = int(input())

def f(n):
if n<10:
return n+n
elif n<100:
return n+(n//10)+(n%10)
elif n<1000:
return n+(n//100)+((n%100)//10)+(n%10)
elif n<10000:
return n+(n//1000)+((n%1000)//100)+((n%100)//10)+(n%10)
elif n<100000:
return n+(n//10000)+((n%10000)//1000)+((n%1000)//100)+((n%100)//10)+(n%10)
elif n<1000000:
return n+(n//100000)+((n%100000)//10000)+((n%10000)//1000)+((n%1000)//100)+((n%100)//10)+(n%10)
else:
return n+1

result = []
for i in range(n):
if n == f(i):
result.append(i)

if result:
print(min(result))
else:
print(0)