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

public class SquareRoute3 {
	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();
			}

			int ans = 0;

			for(int j = 0; j < y.length; j++) {
				for(int i = 0; i < x.length; i++) {
					int py = j + 1;
					int px = i + 1;

					while(px < x.length && py < y.length) {
						int sx = x[px] - x[i];
						int sy = y[py] - y[j];
						if(sx == sy) { ans++; }
						if(sx <= sy) { px ++; }
						if(sx >= sy) { py ++; }
					}
				}
			}

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