from bisect import bisect_left, bisect_right

n, m = map(int, input().split())
X = set()
Y = set()
for _ in range(m):
    x, y = map(int, input().split())
    X.add(x + y)
    Y.add(x - y)
ans = 0
odd = []
even = []
for x in sorted(X):
    ans += min(x - 1, 2 * n - x + 1)
    if x & 1:
        odd.append(x)
    else:
        even.append(x)

for y in Y:
    xx = 1
    yy = xx - y
    if yy <= 0:
        yy = 1
        xx = yy + y
    mi = xx + yy
    xx = n
    yy = xx - y
    if yy > n:
        yy = n
        xx = yy + y
    ma = xx + yy
    if mi & 1:
        p1 = bisect_left(odd, mi)
        p2 = bisect_right(odd, ma)
    else:
        p1 = bisect_left(even, mi)
        p2 = bisect_right(even, ma)
    ans += (ma - mi) // 2 + 1 - (p2 - p1)
print(ans)