import sys
input = sys.stdin.readline
from collections import *

def bfs(s):
    if ma[s]!=-1:
        return
    
    q = deque([s])
    ma[s] = s
    
    while q:
        v = q.popleft()
        
        for nv in G[v]:
            if ma[nv]==-1:
                ma[nv] = s
                q.append(nv)
        
N, M = map(int, input().split())
G = [[] for _ in range(N)]

for _ in range(M):
    B, C = map(int, input().split())
    G[C-1].append(B-1)

ma = [-1]*N

for i in range(N-1, -1, -1):
    bfs(i)
    
print(sum(ma)+N)