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

max_replace = {}

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

cache = {}

def get_max(x):
    if x not in max_replace:
        return x
    if x in cache:
        return cache[x]
    path = []
    current = x
    while current in max_replace and current not in cache:
        path.append(current)
        current = max_replace[current]
    if current in cache:
        res = cache[current]
    else:
        res = current
    for node in path:
        cache[node] = res
    cache[x] = res
    return res

total_increment = 0
for B in max_replace:
    max_val = get_max(B)
    total_increment += (max_val - B)

initial_sum = N * (N + 1) // 2
result = initial_sum + total_increment
print(result)