N,M,T = map(int,input().split())
R = [[0] * N for _ in range(N)]
for _ in range(M):
    a,b = map(int,input().split())
    R[b][a] = 1
def seki(x,y):
    l = [[0] * N for _ in range(N)]
    for i in range(N):
        for j in range(N):
            for k in range(N):
                if x[i][k] and y[k][j]:
                    l[i][j] = 1
    return l
tmp = [[0] * N for _ in range(N)]
for i in range(N):
    tmp[i][i] = 1
while T:
    if T & 1:
        tmp = seki(tmp,R)
    T >>= 1
    R = seki(R,R)
ans = 0
for i in range(N):
    ans += tmp[i][0]
print(ans)