use crate::lib::stdio::*;

fn main() {
    scan!(n: usize, mut ws: [(u64, u64); n]);

    // (w1, s1) の下に (w2, s2) があり、w1 + s1 >= w2 + s2 であるとき、
    // s2 - w1 <= s2, s2 - w1 <= s1 - w2 より、
    // これら 2 つの積み木を swap しても min(s1, s2 - w1) は減少しない。
    ws.sort_unstable_by_key(|&(w, s)| w + s);

    // dp[X]: 条件を満たす X 個の積み木の重みの和の最小値
    let mut dp = vec![u64::MAX; n + 1];
    dp[0] = 0;
    for &(w, s) in &ws {
        for i in (0..n).rev() {
            if dp[i] <= s {
                dp[i + 1] = dp[i + 1].min(dp[i] + w);
            }
        }
    }

    for i in (0..=n).rev() {
        if dp[i] != u64::MAX {
            prtln!(i);
            return;
        }
    }
}



pub mod lib {

pub mod stdio {

pub use crate::prtln;
pub use crate::scan;
use std::io::{stdout, BufWriter, StdoutLock};

pub fn stdout_buf() -> BufWriter<StdoutLock<'static>> {
    let out = Box::leak(Box::new(stdout()));
    BufWriter::new(out.lock())
}

#[macro_export]
macro_rules! prtln {
    (@ $dst:expr, iter=$expr:expr) => { $crate::prtln!(@ $dst, iter=$expr, sep=" "); };
    (@ $dst:expr, iter=$expr:expr, sep=$sep:expr) => { {
        let mut iter = $expr.into_iter();
        if let Some(expr) = iter.next() {
            std::write!($dst, "{}", expr).unwrap();
            for expr in iter { std::write!($dst, "{}{}", $sep, expr).unwrap(); }
        }
        $crate::prtln!(@ $dst, "");
    } };
    (@ $dst:expr, $expr:expr, no eol) => { std::write!($dst, "{}", $expr).unwrap(); };
    (@ $dst:expr, $expr:expr) => { std::writeln!($dst, "{}", $expr).unwrap(); };
    (@ $dst:expr, $expr:expr, $($exprs:expr),*) => { {
        std::write!($dst, "{} ", $expr).unwrap();
        $crate::prtln!(@ $dst, $($exprs),*);
    } };
    (new $var:ident $(,)?) => { let mut $var = stdout_buf(); };
    (new $var:ident, $($t:tt)*) => {
        $crate::prtln!(new $var);
        $crate::prtln!(to $var, $($t)*);
    };
    (to $var:ident, $($t:tt)*) => { {
        use std::io::Write;
        $crate::prtln!(@ $var, $($t)*);
    } };
    ($($t:tt)*) => { {
        $crate::prtln!(new __prtln, $($t)*);
        std::mem::drop(__prtln);
    } };
}

#[macro_export]
macro_rules! scan {
    (@ $iter:expr $(,)?) => {};
    (@ $iter:expr, mut $var:ident : $t:tt $($r:tt)*) => {
        #[allow(non_snake_case)]
        let mut $var = $crate::scan_value!($iter, $t);
        $crate::scan!(@ $iter $($r)*)
    };
    (@ $iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        #[allow(non_snake_case)]
        let $var = $crate::scan_value!($iter, $t);
        $crate::scan!(@ $iter $($r)*)
    };
    (@ $iter:expr, $pat:pat in $t:tt $($r:tt)*) => {
        let $pat = $crate::scan_value!($iter, $t);
        $crate::scan!(@ $iter $($r)*)
    };
    (from $s:expr, $($r:tt)*) => { $crate::scan!(@ $s, $($r)*); };
    (new $var:ident, $($r:tt)*) => {
        let mut __input = String::new();
        std::io::Read::read_to_string(&mut std::io::stdin(), &mut __input).unwrap();
        let $var = &mut __input.split_ascii_whitespace();
        $crate::scan!(@ $var, $($r)*);
    };
    ($($r:tt)*) => { $crate::scan!(new __scan, $($r)*); };
}

#[macro_export]
macro_rules! scan_value {
    ($iter:expr, ( $($t:tt),* )) => { ( $($crate::scan_value!($iter, $t)),* ) };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| $crate::scan_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, bytes) => { $iter.next().unwrap().as_bytes() };
    ($iter:expr, usize1) => { $crate::scan_value!($iter, usize) - 1 };
    ($iter:expr, $t:ty) => { $iter.next().unwrap().parse::<$t>().unwrap() };
}

}  // mod stdio

}  // mod lib