import std.conv, std.functional, std.range, std.stdio, std.string; import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons; import core.bitop; class EOFException : Throwable { this() { super("EOF"); } } string[] tokens; string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; } int readInt() { return readToken.to!int; } long readLong() { return readToken.to!long; } real readReal() { return readToken.to!real; } bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } } bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } } int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; } int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); } int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); } int N; bool[][] mul(bool[][] f, bool[][] g) { auto h = new bool[][](N, N); foreach (u; 0 .. N) foreach (w; 0 .. N) if (f[u][w]) { foreach (v; 0 .. N) if (g[w][v]) { h[u][v] = true; } } return h; } void main() { try { for (; ; ) { N = readInt(); const M = readInt(); const T = readLong(); auto A = new int[M]; auto B = new int[M]; foreach (i; 0 .. M) { A[i] = readInt(); B[i] = readInt(); } auto f = new bool[][](N, N); foreach (i; 0 .. M) { f[A[i]][B[i]] = true; } auto g = new bool[][](N, N); foreach (u; 0 .. N) { g[u][u] = true; } for (long e = T; e; e >>= 1) { if (e & 1) g = mul(g, f); f = mul(f, f); } const ans = g[0].count(true); writeln(ans); } } catch (EOFException e) { } }