use std::io::Read;

fn main() {
	let mut s = String::new();
	std::io::stdin().read_to_string(&mut s).ok();
	let n: Vec<u128> =
		s.split_whitespace().skip(1).flat_map(str::parse).collect();
	let a: u128 = n.chunks(2).map(|a| (a[0] + 1) / 2 * a[1]).sum();
	println!("{}", a % 1000000007)
}