#include <bits/stdc++.h>
using namespace std;
char space[100005];
char tar[100005] = "abcdefghijklmnopqrstuvwxyz";
int main(int argc, char *argv[]) {
  int z = 0;
  scanf("%s", space);
  for (int i = 0; space[i] != '\0'; i++) {
    if (z == 26) break;
    if (space[i] <= tar[z]) {
      space[i] = tar[z];
      z++;
    }
  }
  if (z == 26) {
    printf("%s", space);
    return 0;
  }
  cout << -1;
}
