n=int(input())

dp=[[0,0,0] for i in range(n+1)]
mod=10**9+7
dp[1][1-1] = 1
if n >=2:dp[2][2-1] = 1
if n >=3:dp[3][3-1] = 1
    
for i in range(n):
    for j in range(3):
        if dp[i][j] == 0:
            continue
        for k in range(1,4):
            if j+1 == k:
                continue
            if i + k <= n:
                dp[i+k][k-1] += dp[i][j]
                dp[i+k][k-1] %= mod

print(sum(dp[n])%mod)