using System; using System.Collections; using System.Collections.Generic; using System.Linq; using System.Text; namespace ProgrammingContest { class Writer : IDisposable { private System.IO.TextWriter Out { get; } private StringBuilder Sb { get; } private bool IsReactive { get; } public Writer(string path) : this(new System.IO.StreamWriter(path)) { } public Writer(bool isReactive) : this(null, isReactive) { } public Writer(System.IO.TextWriter writer = null, bool isReactive = false) { this.Out = (writer ?? Console.Out); this.IsReactive = isReactive; if (!this.IsReactive) { this.Sb = new StringBuilder(); } } public void Dispose() { if (!this.IsReactive) { this.Out.Write(Sb.ToString()); } if (!this.Out.Equals(Console.Out)) { this.Out.Dispose(); } } public void Write(object val) { if (this.IsReactive) { this.Out.Write(val.ToString()); this.Out.Flush(); } else { this.Sb.Append(val.ToString()); } } public void WriteFormat(string format, params object[] vals) { if (this.IsReactive) { this.Out.Write(format, vals); this.Out.Flush(); } else { this.Sb.AppendFormat(format, vals); } } public void WriteLine(object val = null) { this.WriteFormat((val ?? string.Empty).ToString() + Environment.NewLine); } public void WriteLine(int val) { this.WriteLine(val.ToString()); } public void WriteLine(long val) { this.WriteLine(val.ToString()); } public void WriteLine(string val) { this.WriteLine((object)val); } public void WriteLine(string format, params object[] vals) { this.WriteFormat(format + Environment.NewLine, vals); } } class Scanner : IDisposable { private Queue Buffer { get; } private char[] Sep { get; } private System.IO.TextReader Reader { get; } public Scanner(string path, char[] sep = null) : this(new System.IO.StreamReader(path), sep) { } public Scanner(System.IO.TextReader reader = null, char[] sep = null) { this.Buffer = new Queue(); this.Sep = (sep ?? new char[] { ' ' }); this.Reader = (reader ?? Console.In); } private void CheckBuffer() { if (this.Buffer.Count == 0 && this.Reader.Peek() != -1) { string str = string.Empty; for (; string.IsNullOrEmpty(str) || string.IsNullOrWhiteSpace(str); str = this.Reader.ReadLine()) ; var strs = str.Split(this.Sep).Where(el => !(string.IsNullOrEmpty(el) || string.IsNullOrWhiteSpace(el))); foreach (var el in strs) { this.Buffer.Enqueue(el); } } } public void Dispose() { if (!this.Reader.Equals(Console.In)) { this.Reader.Dispose(); } } public string Next() { this.CheckBuffer(); return this.Buffer.Dequeue(); } public string[] GetStringArray(int N) { return Enumerable.Range(0, N) .Select(e => this.Next()) .ToArray(); } public int NextInt() { return int.Parse(this.Next()); } public int[] GetIntArray(int N) { return Enumerable.Range(0, N) .Select(e => this.NextInt()) .ToArray(); } public double NextDouble() { return double.Parse(this.Next()); } public double[] GetdoubleArray(int N) { return Enumerable.Range(0, N) .Select(e => this.NextDouble()) .ToArray(); } public long NextLong() { return long.Parse(this.Next()); } public long[] GetLongArray(int N) { return Enumerable.Range(0, N) .Select(e => this.NextLong()) .ToArray(); } public bool IsEnd { get { this.CheckBuffer(); return this.Buffer.Count == 0; } } } class MainClass : IDisposable { private Scanner Sc { get; } private Writer Wr { get; } static string BackPath { get; } = ".."; private char DirSep { get; } = System.IO.Path.DirectorySeparatorChar; private string InFilePath { get; } = string.Empty; private string OutFilePath { get; } = string.Empty; public MainClass() { this.InFilePath = MainClass.BackPath + this.DirSep + MainClass.BackPath + this.DirSep + "in.txt"; this.OutFilePath = MainClass.BackPath + this.DirSep + MainClass.BackPath + this.DirSep + "out.txt"; this.Wr = new Writer(this.IsReactive); //this.Wr = new Writer(this.OutFilePath); #if DEBUG if (!this.IsReactive) { this.Sc = new Scanner(this.InFilePath); } else { this.Sc = new Scanner(); } #else this.Sc = new Scanner(); #endif } static void Main(string[] args) { using (var mainClass = new MainClass()) { mainClass.Solve(); } } public void Dispose() { this.Sc?.Dispose(); this.Wr?.Dispose(); #if DEBUG Console.WriteLine("press any key to continue..."); Console.ReadKey(); #endif } int CalcMod(string val, int mod) => val .Select(c => c - '0') .Cast() .Aggregate((a, b) => (a * 10 + b) % mod); int PowMod(int a, System.Numerics.BigInteger p, int mod) { if (p == System.Numerics.BigInteger.One) { return a; } else if (p == System.Numerics.BigInteger.Zero) { return 1; } else { if (p.IsEven) { var t = PowMod(a, p / 2, mod); return t * t % mod; } else { return a * PowMod(a, p - 1, mod) % mod; } } } void Solve() { string N = Sc.Next(); string K = Sc.Next(); const string V = "285714"; int nMod = CalcMod(N, V.Length); var idx = (PowMod(nMod, System.Numerics.BigInteger.Parse(K), V.Length) - 1 + V.Length) % V.Length; Wr.WriteLine(V[idx].ToString()); } private bool IsReactive { get; } = false; // TODO: reactive check !! } }