#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
const int N = 100100;
char s[N];
int curr = 0;
int main() {
  scanf("%s", s);
  int n = strlen(s);
  for (int i = 0; i < n && curr < 26; i++) {
    if (s[i] - 'a' <= curr) s[i] = 'a' + curr++;
  }
  if (curr != 26) return puts("-1"), 0;
  printf("%s\n", s);
}
