#include<stdio.h>
#include<string.h>
int main(void){
	char c[100005] = {};
	char buf,max;
	int i,j,l,m,k;
	scanf("%s",c);
	l = strlen(c);
	for(i=0;i<l;i++){
		m = i;
		max = '0';
		k=0;
		for(j=i;j<l;j++){
			if(max < c[j]){
				m = j;
				max = c[i];
				k++;
			}
		}
		if(k != 0){
			buf = c[i];
			c[i] = c[m];
			c[m] = buf;
		}
	}
	printf("%s",c);
	return 0;
}