#include <bits/stdc++.h>

using namespace std;

#define int long long


unordered_map<long long, int> Map;

long long A[500000], B[500000];

int32_t main() {
	int n;
	cin >> n;
	for(int i = 1; i <= n; ++i) cin >> A[i];
	for(int i = 1; i <= n; ++i) cin >> B[i];

	Map[0] = 0;
	
	long long s = 0;
	int ans = 0;
	for(int i = 1; i <= n; ++i) {
		s += A[i] - B[i];
		if(Map.find(s) != Map.end()) {
			ans = max(ans, i - Map[s]);
		} else {
			Map[s] = i;
		}
	}

	cout << ans;


	return 0;
}