#![allow(unused_imports)] #![allow(dead_code)] #![allow(non_camel_case_types)] #![allow(non_snake_case)] use std::cmp::*; use std::collections::*; use std::ops::*; use std::io::{Write, BufWriter}; // const MOD: usize = 998244353; const MOD: i64 = 1000000007; // https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 macro_rules! input { ($($r:tt)*) => { let stdin = std::io::stdin(); let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock())); let mut next = move || -> String{ bytes .by_ref() .map(|r|r.unwrap() as char) .skip_while(|c|c.is_whitespace()) .take_while(|c|!c.is_whitespace()) .collect() }; input_inner!{next, $($r)*} }; } macro_rules! input_inner { ($next:expr) => {}; ($next:expr, ) => {}; ($next:expr, $var:ident : $t:tt $($r:tt)*) => { let $var = read_value!($next, $t); input_inner!{$next $($r)*} }; } macro_rules! read_value { ($next:expr, ( $($t:tt),* )) => { ( $(read_value!($next, $t)),* ) }; ($next:expr, [ $t:tt ; $len:expr ]) => { (0..$len).map(|_| read_value!($next, $t)).collect::>() }; ($next:expr, chars) => { read_value!($next, String).chars().collect::>() }; ($next:expr, usize1) => { read_value!($next, usize) - 1 }; ($next:expr, [ $t:tt ]) => {{ let len = read_value!($next, usize); (0..len).map(|_| read_value!($next, $t)).collect::>() }}; ($next:expr, $t:ty) => { $next().parse::<$t>().expect("Parse error") }; } fn solve() { input! { n: i64, } let x = n-1; let t = x/3; let mut sum = if t%2==0 {-((t-1)%MOD)*((t/2)%MOD)%MOD} else {-((t-1)/2%MOD)*(t%MOD)%MOD}; // println!("{}", sum); if x%2==0 && t%2==0 { sum += ((x-1)/2%MOD+(x-t)/2%MOD)%MOD*(t/2%MOD)%MOD; } else if x%2==0 && t%2==1 { sum += ((x-1)/2%MOD+(x-t+1)/2%MOD)%MOD*((t-1)/2%MOD)%MOD + (x-t)/2%MOD; } else if x%2==1 && t%2==0 { sum += (x/2%MOD + (x-t)/2%MOD)%MOD*((t/2+1)/2%MOD)%MOD - x/2%MOD - (x-t)/2%MOD; } else if x%2==1 && t%2==1 { sum += (x/2%MOD + (x-t)/2%MOD)%MOD*((t+1)/2%MOD)%MOD - x/2%MOD; } sum = (sum%MOD+MOD)%MOD; println!("{}", sum); } fn main() { // In order to avoid potential stack overflow, spawn a new thread. let stack_size = 104_857_600; // 100 MB let thd = std::thread::Builder::new().stack_size(stack_size); thd.spawn(|| solve()).unwrap().join().unwrap(); }