H, W = map(int, input().split())

if H == 0:
    print(0)
else:
    W_abs = abs(W)
    if W_abs == 0:
        print(0)
    else:
        D = max(0, H - W_abs + 1)
        R = H - D
        if D > 0:
            steps = D + R * (R + 3) // 2
        else:
            steps = R * (W_abs - H) + R * (R + 1) // 2
        print(steps)