using System; using System.IO; using System.Collections.Generic; using System.Linq; using System.Numerics; using System.Runtime.CompilerServices; using System.Text; using System.Globalization; using System.Threading; using static System.Math; namespace FertiLib.Contest.F { public class Solver { Scanner sr; StreamWriter sw; bool isMultipleTestCases = false; public void Solve() { var (n, m, t) = sr.ReadValue(); var (a, b) = sr.ReadValueArray(m); var vec = new Matrix(n, 1); vec[0, 0] = 1; var matrix = new Matrix(n, n); for (int i = 0; i < m; i++) { matrix[a[i], b[i]] = 1; } var ans = Matrix.Pow(matrix, t) * vec; var ansc = 0; for (int i = 0; i < n; i++) { if (ans[i, 0] == 1) ansc++; } Console.WriteLine(ansc); } public Solver(Scanner cin, StreamWriter cout) { this.sr = cin; this.sw = cout; } public void Start() { int _t = 1; if (isMultipleTestCases) _t = sr.ReadInt(); while (_t-- > 0) Solve(); } public static void YESNO(bool condition) => Console.WriteLine(condition ? "YES" : "NO"); public static void YesNo(bool condition) => Console.WriteLine(condition ? "Yes" : "No"); public static void yesno(bool condition) => Console.WriteLine(condition ? "yes" : "no"); } class Matrix { int row; int column; public long[] value; public Matrix(int r, int c) { value = new long[r * c]; row = r; column = c; } public long this[int r, int c] { get { return this.value[r * column + c]; } set { this.value[r * column + c] = value; } } public static Matrix operator *(Matrix l, Matrix r) { if (l.column != r.row) throw new ArgumentException(); var ret = new Matrix(l.row, r.column); for (int i = 0; i < l.row; i++) { for (int j = 0; j < r.column; j++) { for (int k = 0; k < l.column; k++) { ret[i, j] |= l[i, k] & r[k, j]; } } } return ret; } public Matrix Pow(long n) => Pow(this, n); public static Matrix Pow(Matrix x, long n) { if (x.column != x.row) throw new ArgumentException(); var ret = new Matrix(x.column, x.column); for (int i = 0; i < x.column; i++) { ret[i, i] = 1; } for (long i = 1; i <= n; i *= 2, x *= x) { if (n / i % 2 == 1) ret *= x; } return ret; } } public static class Program { public static void Main(string[] args) { var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false }; Console.SetOut(sw); var cin = new Scanner(); var solver = new Solver(cin, sw); solver.Start(); Console.Out.Flush(); } } public static class Extention { public static string Join(this IEnumerable x, string separator = "") => string.Join(separator, x); public static int UpperBound(this IList list, T value) => list.BinarySearch(value, true, 0, list.Count, Comparer.Default); public static int LowerBound(this IList list, T value) => list.BinarySearch(value, false, 0, list.Count, Comparer.Default); public static int BinarySearch(this IList list, T value, bool isUpperBound, int index, int length, Comparer comparer) { var ng = index - 1; var ok = index + length; while (ok - ng > 1) { var mid = ng + (ok - ng) / 2; var res = comparer.Compare(list[mid], value); if (res < 0 || (isUpperBound && res == 0)) ng = mid; else ok = mid; } return ok; } public static bool Chmax(ref this T a, T b) where T : struct, IComparable { if (a.CompareTo(b) >= 0) return false; a = b; return true; } public static bool Chmin(ref this T a, T b) where T : struct, IComparable { if (a.CompareTo(b) <= 0) return false; a = b; return true; } } public class Scanner { string[] s; int i; char[] separator = new char[] { ' ' }; public Scanner() { s = new string[0]; i = 0; } public string Read() => ReadString(); public string ReadString() { if (i < s.Length) return s[i++]; string st = Console.ReadLine(); while (st == "") st = Console.ReadLine(); s = st.Split(separator, StringSplitOptions.RemoveEmptyEntries); if (s.Length == 0) return ReadString(); i = 0; return s[i++]; } public string[] ReadStringArray(int N) { string[] Array = new string[N]; for (int i = 0; i < N; i++) { Array[i] = ReadString(); } return Array; } public int ReadInt() => int.Parse(ReadString()); public int[] ReadIntArray(int N, int add = 0) { int[] Array = new int[N]; for (int i = 0; i < N; i++) { Array[i] = ReadInt() + add; } return Array; } public long ReadLong() => long.Parse(ReadString()); public long[] ReadLongArray(int N, long add = 0) { long[] Array = new long[N]; for (int i = 0; i < N; i++) { Array[i] = ReadLong() + add; } return Array; } public double ReadDouble() => double.Parse(ReadString()); public double[] ReadDoubleArray(int N, double add = 0) { double[] Array = new double[N]; for (int i = 0; i < N; i++) { Array[i] = ReadDouble() + add; } return Array; } public T1 ReadValue() => (T1)Convert.ChangeType(ReadString(), typeof(T1)); public (T1, T2) ReadValue() { var inputs = ReadStringArray(2); var v1 = (T1)Convert.ChangeType(inputs[0], typeof(T1)); var v2 = (T2)Convert.ChangeType(inputs[1], typeof(T2)); return (v1, v2); } public (T1, T2, T3) ReadValue() { var inputs = ReadStringArray(3); var v1 = (T1)Convert.ChangeType(inputs[0], typeof(T1)); var v2 = (T2)Convert.ChangeType(inputs[1], typeof(T2)); var v3 = (T3)Convert.ChangeType(inputs[2], typeof(T3)); return (v1, v2, v3); } public (T1, T2, T3, T4) ReadValue() { var inputs = ReadStringArray(4); var v1 = (T1)Convert.ChangeType(inputs[0], typeof(T1)); var v2 = (T2)Convert.ChangeType(inputs[1], typeof(T2)); var v3 = (T3)Convert.ChangeType(inputs[2], typeof(T3)); var v4 = (T4)Convert.ChangeType(inputs[3], typeof(T4)); return (v1, v2, v3, v4); } public (T1, T2, T3, T4, T5) ReadValue() { var inputs = ReadStringArray(5); var v1 = (T1)Convert.ChangeType(inputs[0], typeof(T1)); var v2 = (T2)Convert.ChangeType(inputs[1], typeof(T2)); var v3 = (T3)Convert.ChangeType(inputs[2], typeof(T3)); var v4 = (T4)Convert.ChangeType(inputs[3], typeof(T4)); var v5 = (T5)Convert.ChangeType(inputs[4], typeof(T5)); return (v1, v2, v3, v4, v5); } public (T1, T2, T3, T4, T5, T6) ReadValue() { var inputs = ReadStringArray(6); var v1 = (T1)Convert.ChangeType(inputs[0], typeof(T1)); var v2 = (T2)Convert.ChangeType(inputs[1], typeof(T2)); var v3 = (T3)Convert.ChangeType(inputs[2], typeof(T3)); var v4 = (T4)Convert.ChangeType(inputs[3], typeof(T4)); var v5 = (T5)Convert.ChangeType(inputs[4], typeof(T5)); var v6 = (T6)Convert.ChangeType(inputs[5], typeof(T6)); return (v1, v2, v3, v4, v5, v6); } public (T1, T2, T3, T4, T5, T6, T7) ReadValue() { var inputs = ReadStringArray(7); var v1 = (T1)Convert.ChangeType(inputs[0], typeof(T1)); var v2 = (T2)Convert.ChangeType(inputs[1], typeof(T2)); var v3 = (T3)Convert.ChangeType(inputs[2], typeof(T3)); var v4 = (T4)Convert.ChangeType(inputs[3], typeof(T4)); var v5 = (T5)Convert.ChangeType(inputs[4], typeof(T5)); var v6 = (T6)Convert.ChangeType(inputs[5], typeof(T6)); var v7 = (T7)Convert.ChangeType(inputs[6], typeof(T7)); return (v1, v2, v3, v4, v5, v6, v7); } public T1[] ReadValueArray(int N) { var v1 = new T1[N]; for (int i = 0; i < N; i++) { v1[i] = ReadValue(); } return v1; } public (T1[], T2[]) ReadValueArray(int N) { var (v1, v2) = (new T1[N], new T2[N]); for (int i = 0; i < N; i++) { var (t1, t2) = ReadValue(); v1[i] = t1; v2[i] = t2; } return (v1, v2); } public (T1[], T2[], T3[]) ReadValueArray(int N) { var (v1, v2, v3) = (new T1[N], new T2[N], new T3[N]); for (int i = 0; i < N; i++) { var (t1, t2, t3) = ReadValue(); v1[i] = t1; v2[i] = t2; v3[i] = t3; } return (v1, v2, v3); } public (T1[], T2[], T3[], T4[]) ReadValueArray(int N) { var (v1, v2, v3, v4) = (new T1[N], new T2[N], new T3[N], new T4[N]); for (int i = 0; i < N; i++) { var (t1, t2, t3, t4) = ReadValue(); v1[i] = t1; v2[i] = t2; v3[i] = t3; v4[i] = t4; } return (v1, v2, v3, v4); } public (T1[], T2[], T3[], T4[], T5[]) ReadValueArray(int N) { var (v1, v2, v3, v4, v5) = (new T1[N], new T2[N], new T3[N], new T4[N], new T5[N]); for (int i = 0; i < N; i++) { var (t1, t2, t3, t4, t5) = ReadValue(); v1[i] = t1; v2[i] = t2; v3[i] = t3; v4[i] = t4; v5[i] = t5; } return (v1, v2, v3, v4, v5); } public (T1[], T2[], T3[], T4[], T5[], T6[]) ReadValueArray(int N) { var (v1, v2, v3, v4, v5, v6) = (new T1[N], new T2[N], new T3[N], new T4[N], new T5[N], new T6[N]); for (int i = 0; i < N; i++) { var (t1, t2, t3, t4, t5, t6) = ReadValue(); v1[i] = t1; v2[i] = t2; v3[i] = t3; v4[i] = t4; v5[i] = t5; v6[i] = t6; } return (v1, v2, v3, v4, v5, v6); } public (T1[], T2[], T3[], T4[], T5[], T6[], T7[]) ReadValueArray(int N) { var (v1, v2, v3, v4, v5, v6, v7) = (new T1[N], new T2[N], new T3[N], new T4[N], new T5[N], new T6[N], new T7[N]); for (int i = 0; i < N; i++) { var (t1, t2, t3, t4, t5, t6, t7) = ReadValue(); v1[i] = t1; v2[i] = t2; v3[i] = t3; v4[i] = t4; v5[i] = t5; v6[i] = t6; v7[i] = t7; } return (v1, v2, v3, v4, v5, v6, v7); } } }