#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline T gcd(T a, T b) {
  if (b) return gcd(b, a % b);
  return a;
}
template <typename T>
inline T ext_gcd(T a, T b, T& x, T& y) {
  if (a == 0) {
    x = 0;
    y = 1;
    return b;
  }
  T x1, y1;
  T g = ext_gcd(b % a, a, x1, y1);
  x = y1 - (b / a) * x1;
  y = x1;
  return g;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  string s;
  cin >> s;
  char cur = 'a';
  for (long long(i) = 0; i < (long long)s.size(); i++) {
    if (cur > 'z') break;
    if (s[i] <= cur) {
      s[i] = cur;
      cur++;
    }
  }
  if (cur > 'z')
    cout << s << '\n';
  else
    cout << -1 << '\n';
}
