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)