use std::io::Read;

fn main() {
	let mut s = String::new();
	std::io::stdin().read_to_string(&mut s).ok();
	let s: Vec<_> = s.trim().split('\n').collect();
	let a: Vec<u8> = s[1].split_whitespace().flat_map(str::parse).collect();
	let b: Vec<u8> = s[2].split_whitespace().flat_map(str::parse).collect();
	let c = a.iter().zip(b.iter()).filter(|(&a, &b)| a <= b).count();
	println!("{}", c);
}