import sys
sys.setrecursionlimit(10000)
MOD = 10 ** 9 + 7
    
n = int(input())
memo = {}
def dfs(n, max_):
    if n == 0:
        return 1
    elif n < max_:
        return 0
    elif n * 10000 + max_ in memo:
        return memo[n * 10000 + max_]
    ret = 0
    for i in range(max_, n + 1):
        ret += dfs(n - i, i)
        ret %= MOD
    
    memo[n * 10000 + max_] = ret
    return ret
    
print(dfs(n, 3))