import sys

# sys.setrecursionlimit(1000005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = (1 << 63)-1
# inf = (1 << 31)-1
md = 10**9+7
# md = 998244353

def popcnt(a): return bin(a).count("1")

def move(s):
    if s == 0: return to[0]
    t = 0
    for u in range(n):
        if s >> u & 1: t |= to[u]
    return t

n, m, t = LI()
to = [0]*n
for _ in range(m):
    u, v = LI()
    to[u] |= 1 << v

ans = 0
while t:
    if t & 1: ans = move(ans)
    nt = [0]*n
    for u in range(n):
        nt[u] = move(to[u])
    to = nt
    t >>= 1

print(popcnt(ans))