N, M = map(int, input().split())

replace_map = {}

for _ in range(M):
    B, C = map(int, input().split())
    if C > B:
        if B in replace_map:
            if C > replace_map[B]:
                replace_map[B] = C
        else:
            replace_map[B] = C

cache = {}
sum_gain = 0

for B in replace_map:
    current = B
    path = []
    while True:
        if current in cache:
            value = cache[current]
            break
        if current not in replace_map:
            value = current
            break
        path.append(current)
        current = replace_map[current]
    # Update cache for all nodes in the path
    for node in path:
        cache[node] = value
    sum_gain += (value - B)

initial_sum = N * (N + 1) // 2
total = initial_sum + sum_gain

print(total)