n,m,t = map(int,input().split())
e = [[] for i in range(n)]
db = [[set() for j in range(n)] for i in range(70)]

for i in range(m):
    a,b = map(int,input().split())
    db[0][a].add(b)
for i in range(1,60):
    for j in range(n):
        for k in db[i-1][j]:
            db[i][j] |= db[i-1][k]

ans = set([0])
for i in range(60):
    if t >> i & 1:
        nex = set()
        for j in ans:
            nex |= db[i][j]
        ans = nex
print(len(ans))