static void Main(String[] args)
        {
            int n = Convert.ToInt32(Console.ReadLine());
            string[] name = new string[n];
            long[] value = new long[n];
            for (int a0 = 0; a0 < n; a0++)
            {
                string[] tokens_name = Console.ReadLine().Split(' ');
                name[a0] = tokens_name[0];
                value[a0] = Convert.ToInt64(tokens_name[1]);
            }
           Console.WriteLine(ReturnminNumber(name, value));
            Console.ReadKey();
        }

        public static string ReturnminNumber(string[] name,long[] val )
        {
           long min;
            string lapname = "";
            for (int i = 0; i <= name.Length-1; i++)
            {
                if (i == 0) {
                    min = val[i];
                }
                if (val[i] < min && val[i].ToString().ToCharArray().Any(f=>f=='4')&& val[i].ToString().ToCharArray().Any(f => f == '7')) {
                    min = val[i];
                    lapname = name[i];
                }
            }

            return (lapname=="")?"-1":lapname;
        }