#include <bits/stdc++.h>
using namespace std;
const double PI = acos(-1.0);
const double eps = 1e-9;
const int MOD = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const long long INFLL = 0x3f3f3f3f3f3f3f3f;
const int MAXN = 1e5 + 5;
char s[MAXN];
int main() {
  scanf("%s", s + 1);
  int n = strlen(s + 1);
  char now = 'a';
  for (int i = 1; i <= n; i++) {
    if (now == 'z' + 1) break;
    if (s[i] <= now) {
      s[i] = now;
      now++;
    }
  }
  if (now == 'z' + 1) {
    printf("%s\n", s + 1);
  } else
    puts("-1");
  return 0;
}
