def main():
    import sys
    input = sys.stdin.read
    data = input().split()
    idx = 0
    N = int(data[idx])
    idx += 1
    M = int(data[idx])
    idx += 1
    
    max_map = {}
    
    for _ in range(M):
        B = int(data[idx])
        idx += 1
        C = int(data[idx])
        idx += 1
        if B < C:
            if B in max_map:
                if C > max_map[B]:
                    max_map[B] = C
            else:
                max_map[B] = C
    
    memo = {}
    
    def compute_max(x):
        if x not in max_map:
            return x
        if x in memo:
            return memo[x]
        next_x = max_map[x]
        m = compute_max(next_x)
        memo[x] = m
        return m
    
    sum_initial = N * (N + 1) // 2
    sum_diff = 0
    
    for x in max_map:
        m = compute_max(x)
        sum_diff += (m - x)
    
    print(sum_initial + sum_diff)

if __name__ == "__main__":
    main()