#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 20;
int x[maxn], y[maxn];
int main() {
  int n, m;
  while (cin >> n >> m) {
    for (int i = 1; i <= n; i++) scanf("%d", &x[i]);
    for (int j = 1; j <= m; j++) scanf("%d", &y[j]);
    int ans = 0;
    int p1 = 1, p2 = 1;
    long long sum1 = 0, sum2 = 0;
    while (p1 <= n || p2 <= m) {
      if (sum1 <= sum2) {
        if (p1 > n) break;
        sum1 += x[p1++];
      } else {
        if (p2 > m) break;
        sum2 += y[p2++];
      }
      if (sum1 == sum2) ans++;
    }
    printf("%d\n", ans);
  }
  return 0;
}
