#include <bits/stdc++.h>
using namespace std;
int main()
{
    int l = 0;
    string s;
    char c;
    while (cin >> c)
    {
        s += c;
        ++l;
    }
    for (int i = 0;i < l;i++)
    {
        if (s[i] != '-') 
        {
            cout << s[i];
        }
        else
        {
            if (i == 0 || i == l - 1)
            {
                cout << "-";
            }
            else if ((s[i - 1] >= s[i + 1]) || (s[i - 1] >= '0' && s[i - 1] <= '9' && s[i + 1] >= 'a' && s[i + 1] <= 'z'))
            {
                cout << '-';
            }
            else
            {
                for (char j = s[i - 1] + 1;j < s[i + 1];j++)
                {
                    cout << j;
                }
            }
        }
    }
}