# やり方違った気がするが1次元dp
# dp[i]Pを置く場合数、答えは最後の3項の合計

N = int(input())
mod = 10**9+7
dp = [0]*(N+1)
dp[0] = 1
for i in range(N+1):
    dp[i] %= mod
    if i+2 <= N:
        dp[i+2] += dp[i]
    if i+3 <= N:
        dp[i+3] += dp[i]
if N == 1:
    ans = 1
elif N == 2:
    ans = 2
elif N >= 3:
    ans = dp[N]+dp[N-1]+dp[N-2]
    ans %= mod
print(ans)