Олимпиадный тренинг

Задача 38312. Minimum number


Given a natural four-digit number. Find the smallest natural four-digit number that contains the same digits as the given one. Note that four-digit numbers cannot start with a zero.

Input
A natural four-digit number is entered.

Imprint
Print the minimum natural  four-digit number consisting of the same digits.
Examples
# Input Output
1 1513 1135