class Program
{
    static void Main(string[] args)
    {
        string[] inputTop = Console.ReadLine()!.Split(' ');
        string[] inputBottom = Console.ReadLine()!.Split(' ');

        decimal numTop = decimal.Parse(inputTop[1]);
        decimal numBottom = decimal.Parse(inputBottom[1]);

        if (numBottom > numTop)
        {
            Console.WriteLine(inputBottom[0]);
        }
        else if (numTop > numBottom)
        {
            Console.WriteLine(inputTop[0]);
        }
        else
        {
            Console.WriteLine(-1);
        }
    }
}