use std::cmp::*; // 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, $t:ty) => ($next().parse::<$t>().expect("Parse error")); } const INF: i64 = 1 << 50; fn main() { input! { n: usize, cd: [(i64, i64); n], } let s: i64 = cd.iter().map(|&(c, d)| c + d).sum(); let mut dp = vec![0; n + 1]; let mut st = vec![(cd[n - 1].0, 0, cd[n - 1].0)]; for i in (0..n).rev() { let (c, d) = cd[i]; if i + 1 < n { let mut ndp = dp[i + 1]; while let Some((sc, sdp, accmi)) = st.pop() { if sc >= c { ndp = min(ndp, sdp); continue; } st.push((sc, sdp, accmi)); break; } let accmi = if let Some(&v) = st.last() { v.2 } else { INF }; st.push((c, ndp, min(accmi, c + ndp))); } dp[i] = -d + st.last().unwrap().2; } println!("{}", s + dp[0]); }