#include <bits/stdc++.h>
using namespace std;
char s[100010];
int len;
int pos[30];
int main() {
  gets(s);
  len = strlen(s);
  memset(pos, -1, sizeof(pos));
  pos[0] = 0;
  for (int i = 0; i < len; i++) {
    int id = s[i] - 'a' + 1;
    for (int j = 26; j >= id; j--) {
      if (pos[j - 1] == -1) continue;
      pos[j] = 1;
      s[i] = 'a' + j - 1;
      break;
    }
  }
  if (pos[26] != -1) {
    puts(s);
  } else
    cout << -1;
}
