use proconio::{fastout, input};

#[fastout]
fn main() {
    input! {
        n: u32,
    }

    println!("{}", output(solve(n)));
}

const fn prepare() -> [u32; 1_000_001] {
    let mut dp = [[0; 3]; 1_000_001];
    let mut ans = [0; 1_000_001];
    dp[0] = [0, 0, 0];
    ans[0] = 1;
    dp[1] = [1, 0, 0];
    ans[1] = 1;
    dp[2] = [0, 1, 0];
    ans[2] = 1;
    dp[3] = [1, 1, 1];
    ans[3] = 3;

    let mut i = 4;
    const MOD: u32 = 1_000_000_007;
    while i < 1_000_001 {
        dp[i][0] = (dp[i - 1][1] + dp[i - 1][2]) % MOD;
        dp[i][1] = (dp[i - 2][0] + dp[i - 2][2]) % MOD;
        dp[i][2] = (dp[i - 3][0] + dp[i - 3][1]) % MOD;
        ans[i] = (dp[i][0] + dp[i][1] + dp[i][2]) % MOD;
        i += 1;
    }
    ans
}

fn solve(n: u32) -> u32 {
    const ANS: [u32; 1_000_001] = prepare();
    ANS[n as usize]
}

fn output(ans: u32) -> u32 {
    ans
}