import sys

# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
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 = 10**16
# md = 998244353
md = 10**9+7

from collections import defaultdict
from heapq import *

n, m = LI()
to = defaultdict(list)
uu = set()
for _ in range(m):
    u, v = LI()
    to[v].append(u)
    uu.add(u)
    uu.add(v)

dp = defaultdict(int)
hp = []
for u in uu:
    heappush(hp, (-u, u))
    dp[u] = u

while hp:
    d, u = heappop(hp)
    d = -d
    if d < dp[u]: continue
    for v in to[u]:
        if dp[v] >= d: continue
        dp[v] = d
        heappush(hp, (-d, v))
# print(dp)

ans = n*(n+1)//2
for u, d in dp.items():
    ans += d-u
print(ans)