#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;

#define REP(i,n) for(int i = 0; i < static_cast<int>(n); ++i)
#define REP2(i,s,n) for(int i = (s); i < static_cast<int>(n); ++i)

typedef vector<int>::iterator vit; 


class RoadSquare {
  vector<int> h, w, h2, w2;
public:
  RoadSquare (int n, int m): h(n), w(m) {}

  void input() {
    REP(i, h.size()) { scanf("%d", &h[i]); }
    REP(i, w.size()) { scanf("%d", &w[i]); }
  }

  int calc() {
    REP(i, h.size()) {
      int hsum = 0;
      REP2(j, i, h.size()) {
        hsum += h[j];
        h2.push_back(hsum); 
      }
    }

    REP(i, w.size()) {
      int wsum = 0;
      REP2(j, i, w.size()) {
        wsum += w[j];
        w2.push_back(wsum);
      }
    }

    sort(w2.begin(), w2.end());
    int count = 0;
    REP(i, h2.size()) {
      pair<vit, vit> p = equal_range(w2.begin(), w2.end(), h2[i]);
      count += distance(p.first, p.second);
    }
    return count;
  }
};


int main() {
  int n, m;
  while (scanf("%d%d", &n, &m), n) {
    RoadSquare rs(n, m);
    rs.input();
    printf("%d\n", rs.calc());
  }
}