766d2a

#include <bits/stdc++.h>
using namespace std;

main()
{
    string first_str, second_str;

    cin >> first_str >> second_str;

    int count = max(first_str.size(), second_str.size()), temp;

    temp = count;

    for (int i = 0; i < first_str.size(); i++)
    {
        for (int j = 0; j < second_str.size(); j++)
        {
            if (first_str[i] == second_str[j])
            {
                temp--;
                break;
            }
        }
        if(temp < count)
        {
            break;
        }
    }

    if (temp <= 0)
    {
        count = -1;
    }

    cout << count;
}