#include<stdio.h>
#include<string.h>
int main()
{
	char a[201],t;
	int i,j;
	while(gets(a)!=NULL)
	{
	for(i=0;i<strlen(a);i++)
		for(j=i;j<strlen(a);j++)
			if(a[i]>a[j])
			{
				t=a[i];
				a[i]=a[j];
				a[j]=t;
			}
	puts(a);
	}
	return 0;
}
/**************************************************************
	Problem: 2201
	User: admin
	Language: C
	Result: Accepted
	Time:32 ms
	Memory:1036 kb
****************************************************************/