mod = 10**9+7

def main():

    n, m, t = map(int, input().split())
    A = [[0]*n for i in range(n)]
    for i in range(m):
        a, b = map(int, input().split())
        A[b][a] = 1
    #print(A)
    # A*B
    def mat_mul(A, B, mod):
        C = [[0]*len(B[0]) for i in range(len(A))]
        for i in range(len(A)):
            for k in range(len(B)):
                for j in range(len(B[0])):
                    C[i][j] = (C[i][j] + A[i][k]*B[k][j])%mod
        return C

    #A**n
    def mat_pow(A, n, mod):
        B = [[0]*len(A) for i in range(len(A))]
        for i in range(len(A)):
            B[i][i] = 1
        while n > 0:
            if n & 1 == 1:
                B = mat_mul(A, B, mod)
            A = mat_mul(A, A, mod)
            n = n>>1
        return B

    X = [0]*n
    X[0] = 1
    A = mat_pow(A, t, mod)
    ans = 0
    for i in range(n):
        s = 0
        for j in range(n):
            s += A[i][j]*X[j]
        if s:
            ans += 1
    #print(A)
    print(ans)

if __name__ == '__main__':
    main()