N = int(input())

if N == 1:
    print(1)
    exit()
elif N == 2:
    print(1)
    exit()
elif N == 3:
    print(3)
    exit()
    
dp = [[0, 0, 0] for _ in range(N+1)]
dp[1] = [1, 0, 0]
dp[2] = [0, 1, 0]
dp[3] = [1, 1, 1]
MOD = 10 ** 9 + 7

for i in range(4, N+1):
    dp[i][0] = dp[i-1][1] + dp[i-1][2]
    dp[i][0] %= MOD
    dp[i][1] = dp[i-2][0] + dp[i-2][2]
    dp[i][1] %= MOD
    dp[i][2] = dp[i-3][0] + dp[i-3][1]
    dp[i][2] %= MOD

print(sum(dp[N]) % MOD)