import sys
from collections import defaultdict

def main():
    N, M = map(int, sys.stdin.readline().split())
    operations = []
    s = set()
    for _ in range(M):
        B, C = map(int, sys.stdin.readline().split())
        if C > B:
            operations.append((B, C))
            s.add(B)
            s.add(C)
    
    # No valid operations
    if not s:
        print(N * (N + 1) // 2)
        return
    
    sorted_v = sorted(s, reverse=True)
    b_to_cs = defaultdict(list)
    for B, C in operations:
        b_to_cs[B].append(C)
    
    max_val = {}
    for v in sorted_v:
        current_max = v
        for C in b_to_cs.get(v, []):
            c_max = max_val.get(C, C)
            if c_max > current_max:
                current_max = c_max
        max_val[v] = current_max
    
    total = N * (N + 1) // 2
    for v in s:
        total += (max_val[v] - v)
    print(total)

if __name__ == "__main__":
    main()