#include <bits/stdc++.h>

using namespace std;


queue<int> a, b;

signed main(){
	int n, m;
	cin >> n >> m;
	
	for(int i = 1; i <= n; ++i){
		int x; cin >> x;
		a.push(x);
	}	
	
	for(int i = 1; i <= m; ++i){
		int x; cin >> x;
		b.push(x);
	}
	
	int cnt = 0;
	while(a.size() || b.size()){
		int top1 = a.front(), top2 = b.front();
		a.pop(), b.pop();
		while(top1 != top2){
			if(top1 < top2){
				top1 += a.front();
				++cnt;
				a.pop();
			}else{
				top2 += b.front();
				++cnt;
				b.pop();
			}
		}
	}
	
	cout << cnt << endl;
	
    return 0;
}