N = int(input())
MOD = 10**9 + 7

dp = [[0]*3 for _ in range(N+1)]
dp[0][2] = 1

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

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