#include <bits/stdc++.h>
using namespace std;
const int N = 1e5;
void read(long long &x) {
  char ch;
  bool flag = 0;
  for (ch = getchar(); !isdigit(ch) && ((flag |= (ch == '-')) || 1);
       ch = getchar())
    ;
  for (x = 0; isdigit(ch); x = (x << 1) + (x << 3) + ch - 48, ch = getchar())
    ;
  x *= 1 - 2 * flag;
}
void print(long long x) {
  if (x > 9) print(x / 10);
  putchar(x % 10 + 48);
}
void write(long long x) {
  if (x < 0) putchar('-');
  print(((x) < 0 ? (-(x)) : (x)));
}
char ch[N + 5];
int len, flag, tmp = -1;
void work() {
  scanf("%s", ch);
  len = strlen(ch);
  for (int i = 0; i < len; i++) {
    if (ch[i] - 'a' <= tmp)
      ++tmp, ch[i] = 'a' + tmp;
    else if (ch[i] - 'a' == tmp + 1)
      ++tmp;
    if (tmp == 25) break;
  }
  if (tmp < 25)
    puts("-1");
  else
    puts(ch);
}
int main() {
  work();
  return 0;
}
