#include <bits/stdc++.h>
using namespace std;
const int N = 100005;
char s[N];
int n, now;
bool flag = 0;
int main() {
  scanf("%s", s + 1);
  n = strlen(s + 1);
  for (int i = 1; i <= n; ++i) {
    int v = s[i] - 'a';
    if (v <= now) {
      s[i] = now + 'a';
      ++now;
      if (now >= 26) {
        flag = 1;
        break;
      }
    }
  }
  if (!flag) {
    puts("-1");
    return 0;
  }
  for (int i = 1; i <= n; ++i) putchar(s[i]);
  putchar('\n');
  return 0;
}
