#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const long long INF64 = 0x3f3f3f3f3f3f3f3f;
const double eps = 1e-8;
const double PI = acos(-1);
template <class T>
T gcd(T a, T b) {
  if (!b) return a;
  return gcd(b, a % b);
}
const int maxn = 1e5 + 10;
char s[maxn];
int check() {
  int n = strlen(s);
  char now = 'a';
  for (int i = 0; i < n; i++) {
    if (s[i] <= now) s[i] = now++;
    if (now > 'z') return 1;
  }
  return 0;
}
int main() {
  scanf("%s", s);
  if (check())
    printf("%s\n", s);
  else
    printf("-1\n");
  return 0;
}
