import java.io.*;
import java.util.*;

public class SquareRoute1 {
	private static final Scanner cin = new Scanner(System.in);

	public static void main(String[] args) {
		while(true) {
			int n = cin.nextInt();
			int m = cin.nextInt();

			if(n == 0 && m == 0) { break; }

			int[] y = new int[n+1];
			int[] x = new int[m+1];

			for(int i = 1; i <= n; i++) {
				y[i] = y[i-1] + cin.nextInt();
			}

			for(int i = 1; i <= m; i++) {
				x[i] = x[i-1] + cin.nextInt();
			}

			Map<Integer,Integer> cnt = new HashMap<Integer,Integer>();

			for(int i = 0; i < y.length; i++) {
				for(int j = 0; j < x.length; j++) {
					int key = x[i] + y[j];
					int cur = cnt.containsKey(key) ? cnt.get(key) : 0;
					cnt.put(key, cur + 1);
				}
			}

			int ans = 0;

			for(int key : cnt.keySet()) {
				ans += cnt.get(key) * (cnt.get(key) - 1) / 2;
			}

			System.out.println(ans);
		}
	}
}