import Foundation

struct Scanner {
    private var elements = [String]()
    private var index = 0

    mutating func peek() -> String {
        while elements.count == index {
            elements = readLine()!.split(separator: " ").map(String.init)
            index = 0
        }
        return elements[index]
    }

    mutating func next() -> String {
        defer { index += 1 }
        return peek()
    }

    mutating func nextInt() -> Int {
        return Int(next())!
    }

    mutating func nextInts(_ n: Int) -> [Int] {
        return (0 ..< n).map { _ in nextInt() }
    }

    mutating func nextDouble() -> Double {
        return Double(next())!
    }
}

let mod = 1000000007

struct Zn: CustomStringConvertible, AdditiveArithmetic {
    let n: Int

    init(_ n: Int) {
        self.n = n
    }

    var description: String {
        String(self.n)
    }

    static var zero = Zn(0)
    static var one = Zn(1)

    static func + (lhs: Self, rhs: Self) -> Self {
        let n = lhs.n + rhs.n
        return Zn(n < mod ? n : n - mod)
    }

    static func + (lhs: Self, rhs: Int) -> Self {
        return lhs + Zn(rhs)
    }

    static func + (lhs: Int, rhs: Self) -> Self {
        return Zn(lhs) + rhs
    }

    static func - (lhs: Self, rhs: Self) -> Self {
        let n = lhs.n - rhs.n
        return Zn(n >= 0 ? n : n + mod)
    }

    static func - (lhs: Self, rhs: Int) -> Self {
        return lhs - Zn(rhs)
    }

    static func - (lhs: Int, rhs: Self) -> Self {
        return Zn(lhs) - rhs
    }

    static func * (lhs: Self, rhs: Self) -> Self {
        Zn((lhs.n * rhs.n) % mod)
    }

    static func * (lhs: Self, rhs: Int) -> Self {
        return lhs * Zn(rhs)
    }

    static func * (lhs: Int, rhs: Self) -> Self {
        return Zn(lhs) * rhs
    }

    static func / (lhs: Zn, rhs: Zn) -> Self {
        return lhs * rhs.inverse
    }

    static func / (lhs: Int, rhs: Zn) -> Self {
        return Zn(lhs) * rhs.inverse
    }

    static func / (lhs: Zn, rhs: Int) -> Self {
        return lhs * Zn(rhs).inverse
    }

    static func += (lhs: inout Self, rhs: Self) {
        lhs = lhs + rhs
    }

    static func += (lhs: inout Self, rhs: Int) {
        lhs = lhs + Zn(rhs)
    }

    static func -= (lhs: inout Self, rhs: Self) {
        lhs = lhs - rhs
    }

    static func -= (lhs: inout Self, rhs: Int) {
        lhs = lhs - Zn(rhs)
    }

    static func *= (lhs: inout Self, rhs: Self) {
        lhs = lhs * rhs
    }

    static func *= (lhs: inout Self, rhs: Int) {
        lhs = lhs * Zn(rhs)
    }

    static func /= (lhs: inout Self, rhs: Self) {
        lhs = lhs / rhs
    }

    static func /= (lhs: inout Self, rhs: Int) {
        lhs = lhs / Zn(rhs)
    }

    func pow(_ n: Int) -> Self {
        if n == 0 {
            return Zn(1)
        } else if n % 2 == 1 {
            return self * self.pow(n - 1)
        } else {
            return (self * self).pow(n / 2)
        }
    }

    var inverse: Self {
        self.pow(mod - 2)
    }
}

struct Array2D<Element> {
    let n1: Int
    let n2: Int
    private var elements: [Element]

    init(repeating: Element, _ n1: Int, _ n2: Int) {
        self.n1 = n1
        self.n2 = n2
        self.elements = [Element](repeating: repeating, count: n1 * n2)
    }

    subscript(i: Int, j: Int) -> Element {
        get {
            elements[i * n2 + j]
        }
        set {
            elements[i * n2 + j] = newValue
        }
    }
}

var scanner = Scanner()
let N = scanner.nextInt()
let M = scanner.nextInt()
let T = scanner.nextInt()

var A = Array2D<Bool>(repeating: false, N, N)

func * (lhs: Array2D<Bool>, rhs: Array2D<Bool>) -> Array2D<Bool> {
    var result = Array2D<Bool>(repeating: false, lhs.n1, rhs.n2)
    let n = lhs.n1
    for i in 0 ..< n {
        for j in 0 ..< n {
            for k in 0 ..< n {
                result[i, j] = result[i, j] || (lhs[i, k] && rhs[k, j])
            }
        }
    }
    return result
}

func power(_ a: Array2D<Bool>, _ k: Int) -> Array2D<Bool> {
    if k == 0 {
        var result = Array2D<Bool>(repeating: false, a.n1, a.n1)
        for i in 0 ..< a.n1 {
            result[i, i] = true
        }
        return result
    } else if k % 2 == 1 {
        return a * power(a, k - 1)
    } else {
        return power(a * a, k / 2)
    }
}

for _ in 0 ..< M {
    let a = scanner.nextInt()
    let b = scanner.nextInt()
    A[b, a] = true
}
let B = power(A, T)

var answer = 0
for i in 0 ..< N {
    if B[i, 0] {
        answer += 1
    }
}
print(answer)