#include <bits/stdc++.h>
using namespace std;
char s[100000 + 10];
char a[] = {"abcdefghijklmnopqrstuvwxyz"};
int main() {
  scanf("%s", s);
  int n = strlen(s);
  int A = 0;
  for (int i = 0; i < 26; i++) {
    int flag = 1;
    for (int j = A; j < n; j++) {
      if (a[i] >= s[j]) {
        s[j] = a[i];
        A = j + 1;
        flag = 0;
        break;
      }
    }
    if (flag != 0) {
      printf("-1\n");
      return 0;
    }
  }
  printf("%s\n", s);
  return 0;
}
