using System;
namespace MyCompiler {
    class Program {
        public static void Main(string[] args) {
            string type = Console.ReadLine();
            
            if (type == "b" | type == "B"){
                int y = int.Parse(Console.ReadLine());
                int x = int.Parse(Console.ReadLine());
                int m = int.Parse(Console.ReadLine());
                int B1 = x * m;
                int B2 = y - B1;
                Console.WriteLine(B2);
            }
            
            if (type == "m" | type == "M"){
                double y1 = double.Parse(Console.ReadLine());
                double x1 = double.Parse(Console.ReadLine());
                double x2 = double.Parse(Console.ReadLine());
                double y2 = double.Parse(Console.ReadLine());
                double y3 = y2 - y1;
                double x3 = x2 - x1;
                double slope = y3 / x3;
                Console.WriteLine(slope);
                

                
            }
        }
        
    }
}