## https://yukicoder.me/problems/no/1816

from collections import deque

def main():
    N, M = map(int, input().split())
    bc = []
    for _ in range(M):
        b, c = map(int, input().split())
        bc.append((b, c))
    
    # 数の集合を計算
    number_set = set()
    for b, c in bc:
        number_set.add(b)
        number_set.add(c)
    number_list = list(number_set)
    number_list.sort(reverse=True)

    # グラフを構築
    next_nodes = {}
    for b, c in bc:
        if c not in next_nodes:
            next_nodes[c] = []
        next_nodes[c].append(b)

    max_numbers = {}
    for n in number_list:
        if n in max_numbers:
            continue

        max_numbers[n] = n
        queue = deque()
        queue.append(n)
        while len(queue) > 0:
            v = queue.popleft()
            if v in next_nodes:
                for w in next_nodes[v]:
                    if w in max_numbers:
                        continue
                    max_numbers[w] = n
                    queue.append(w)

    answer = (N * (N + 1)) // 2
    for n, v in max_numbers.items():
        answer += -n + v
    print(answer)





if __name__ == "__main__":
    main()