import sys
from collections import defaultdict

def main():
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx])
    idx += 1
    M = int(input[idx])
    idx += 1

    valid_ops = []
    for _ in range(M):
        B = int(input[idx])
        idx += 1
        C = int(input[idx])
        idx += 1
        if C > B:
            valid_ops.append((B, C))

    max_replace = defaultdict(int)
    for B, C in valid_ops:
        if B in max_replace:
            if C > max_replace[B]:
                max_replace[B] = C
        else:
            max_replace[B] = C

    if not max_replace:
        print(N * (N + 1) // 2)
        return

    nodes = set()
    for B in max_replace:
        nodes.add(B)
        nodes.add(max_replace[B])
    nodes = sorted(nodes, reverse=True)

    max_value = {k: k for k in nodes}
    for k in nodes:
        if k in max_replace:
            c = max_replace[k]
            if max_value[c] > max_value[k]:
                max_value[k] = max_value[c]

    original = N * (N + 1) // 2
    delta = 0
    for B in max_replace:
        delta += (max_value[B] - B)
    print(original + delta)

if __name__ == "__main__":
    main()