#include <stdio.h>
int main() {
char s[20];
scanf("%s", s);
int n = 0;
while (s[n] != '\0') n++;
int pos = -1;
for (int i = 0; i < n - 1; i++) {
for (int j = i + 1; j < n; j++) {
if (s[j] > s[i]) {
pos = i;
break;
}
}
if (pos != -1) break;
}
if (pos == -1) {
printf("%s\n", s);
return 0;
}
char max_digit = s[pos + 1];
int max_pos = pos + 1;
for (int j = pos + 2; j < n; j++) {
if (s[j] >= max_digit) {
max_digit = s[j];
max_pos = j;
}
}
char temp = s[pos];
s[pos] = s[max_pos];
s[max_pos] = temp;
printf("%s\n", s);
return 0;
}