import sys

input = sys.stdin.buffer.readline
#  nxnの行列積
# n is necessary


n, m, t = map(int, input().split())

graph = [[0] * (n) for _ in range(n)]
for _ in range(m):
    a, b = map(int, input().split())
    a, b = a - 1, b - 1
    graph[a][b] = 1


#  nxnの行列積
# n is necessary
mod = 10 ** 9 + 7


def matrix_product(A, B, mod):
    res = [[0] * n for _ in range(n)]
    for i in range(n):
        for k in range(n):
            for j in range(n):
                res[i][j] += A[i][k] * B[k][j]
                res[i][j] %= mod
    return res


def matrix_exponents(A, t, mod):
    res = [[0] * n for _ in range(n)]
    for i in range(n):
        res[i][i] = 1
    while t > 0:
        if t & 1 == 1:
            res = matrix_product(res, A, mod)
        A = matrix_product(A, A, mod)
        t //= 2
    return res


res1 = matrix_exponents(graph, t, 13)
res2 = matrix_exponents(graph, t, 11)
ans = 0

for j in range(n):
    if res1[0][j] > 0 or res2[0][j]:
        ans += 1

print(ans)