Prob D

Notes : IN C LANGUAGE

This is Sorting

DONT USE VOID MAIN

INPUT AND OUTPUT MUST BE SAME

Malfunctioning Keyswitches The switch of every keys in Jejg's mechanical keyboard are weird. Characters are typed more times than the keys are pressed. Given S, determine the shortest ordering of key- press Joje did. Format Input The only line of input contains S, the string of typed characters. Format Output The output of this problem will be the order of keypresses. Constraints .13 |S