using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; class Program { static void Main() { solve(); } static void solve() { Scanner scanner = new Scanner(); int a = scanner.nextInt(), b = scanner.nextInt(); Console.WriteLine(a ^ b); } } class Scanner { string[] s; int i; char[] cs = new char[] { ' ' }; public Scanner() { s = new string[0]; i = 0; } public string next() { if (i < s.Length) return s[i++]; string st = Console.ReadLine(); while (st == "") st = Console.ReadLine(); s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries); i = 0; return next(); } public int nextInt() { return int.Parse(next()); } public long nextLong() { return long.Parse(next()); } public double nextDouble() { return double.Parse(next()); } }