CF233B Non-square Equation

Let's consider equation: $ x^{2}+s(x)·x-n=0, $ where $ x,n $ are positive integers, $ s(x) $ is the function, equal to the sum of digits of number $ x $ in the decimal number system. You are given an integer $ n $ , find the smallest positive integer root of equation $ x $ , or else determine that there are no such roots.

A single line contains integer $ n $ $ (1

Print -1, if the equation doesn't have integer positive roots. Otherwise print such smallest integer $ x $ $ (x>0) $ , that the equation given in the statement holds.

In the first test case $ x=1 $ is the minimum root. As $ s(1)=1 $ and $ 1^{2}+1·1-2=0 $ . In the second test case $ x=10 $ is the minimum root. As $ s(10)=1+0=1 $ and $ 10^{2}+1·10-110=0 $ . In the third test case the equation has no roots.