M = 1000
DM = M * 2 + 1
 
def count(n):
    global M
    res = n + 1
    if n > M:
        res -= (n-M) * 2
    return res
 
def solve(n):
    cnt = 0
    for a in range(min(DM, n), -1, -1):
        b = n - a
        if b > DM:
            break
        cnt += count(a) * count(b)
    return cnt
 
while True:
    try:
        l = input()
    except EOFError:
        break
    nm = int(l)
    print(solve(nm))