using System; using System.Collections.Generic; using System.Linq; public class MyLib { public static List GetIntListFromTextReader(System.IO.TextReader reader, char delimitor) { return reader.ReadLine().Split( delimitor ).ToList().ConvertAll( int.Parse ); } public static void WriteTextStream(System.IO.TextWriter writer, object args) { writer.WriteLine( args ); } } public class Program { public static int Solver(System.IO.TextReader input) { var remains = Enumerable.Range( 1, 10 ).ToList(); var b = MyLib.GetIntListFromTextReader( input, ' ' ); foreach (var n in b) { remains.Remove( n ); } return remains.ElementAt( 0 ); } private static void Main() { Solver( Console.In ); } }