n, m = map(int, input().split())

max_map = {}

for _ in range(m):
    b, c = map(int, input().split())
    if c > b:
        if b not in max_map or c > max_map[b]:
            max_map[b] = c

cache = {}

def get_final(i):
    if i not in max_map:
        return i
    if i in cache:
        return cache[i]
    path = []
    current = i
    while current in max_map:
        if current in cache:
            final = cache[current]
            break
        path.append(current)
        current = max_map[current]
    else:
        final = current
    # Update cache for all nodes in the path
    for node in path:
        cache[node] = final
    return final

total = n * (n + 1) // 2

for b in max_map:
    final = get_final(b)
    total += (final - b)

print(total)