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

int main()
{
  int h,w;
  while(scanf("%d%d",&h,&w),h|w) {
    vector<int> hsum,wsum;
    hsum.push_back(0);
    for (int i=0;i<h;++i) {
      int v; scanf("%d",&v);
      hsum.push_back(hsum.back()+v);
    }

    wsum.push_back(0);
    for (int i=0;i<w;++i) {
      int v; scanf("%d",&v);
      wsum.push_back(wsum.back()+v);
    }
    
    map<int,int> wm,hm;
    for (int i=0;i<hsum.size();++i)
      for (int j=i+1;j<hsum.size();++j)
	++hm[hsum[j]-hsum[i]];
    for (int i=0;i<wsum.size();++i)
      for (int j=i+1;j<wsum.size();++j)
	++wm[wsum[j]-wsum[i]];

    int ans=0;
    for (map<int,int>::iterator it=hm.begin();it!=hm.end();++it) {
      map<int,int>::iterator jt=wm.find(it->first);
      if (jt==wm.end()) continue;
      ans+=it->second*jt->second;
    }
    printf("%d\n",ans);
  }
}