import sys

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


def matrix_product(A, B):
    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]
                if res[i][j]:
                    res[i][j] = 1
    return res


def matrix_exponents(A, t):
    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)
        A = matrix_product(A, A)
        t //= 2
    return res


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

res = matrix_exponents(graph, t)
ans = 0

for j in range(n):
    if res[j][0]:
        ans += 1

print(ans)