#include<stdio.h>
int main()
{
char a[10], ch;
int i = 0, j, k;
while ((a[i] = getchar()) != '\n')
i++;
for (j = 0; j<i; j++)
{
ch = a[j];
for (k = j + 1; k<i; k++)
{
if (ch<a[k])
{
ch = a[k];
a[k] = a[j];
a[j] = ch;
}
}
}
for (k = 0; k<i; k++)
putchar(a[k]);
getchar();
return 0;
}