It's only another flesh wound Part 1

$\large \square\square \ - \ \square\square \ - \ \square\square$

You are given that the numbers $1,2,3,4,5,6$ are to be filled in the square boxes as shown above (without repetition) such that it represents a 2 digit integer subtracting two 2-digit integers.

Of all $6!=720$ possible arrangements, find the smallest positive resultant number.

Details and Assumptions

As an explicit example, we can have $56 - 34 - 12 = 10$ as a resultant number.

See Part 2 .