n = int(input())
if n == 1:
    print(1)
    exit()
if n == 2:
    print(1)
    exit()
mod = 10**9+7
dp = [[0]*3 for i in range(n+1)]
dp[1][0] = 1
dp[2][1] = 1
dp[3][2] = 1

for i in range(n):
    for j in range(3):
        for k in range(3):
            if j == k:
                continue
            if i+k+1 <= n:
                dp[i+k+1][k] += dp[i][j]%mod
#print(dp)
print(sum(dp[n])%mod)