#include <iostream>
#include <stack>
#include <map>

using namespace std;

const int NMAX = 100000;

int n;

long long s1[NMAX];
long long s2[NMAX];

long long s[NMAX];

map <long long, int> m;


void citeste() {
	cin >> n;

	for (int i = 1; i <= n; i++) {
		cin >> s1[i]; s1[i] = s1[i - 1] + s1[i];
	}

	
	for (int i = 1; i <= n; i++) {
		cin >> s2[i]; s2[i] = s2[i - 1] + s2[i];
	}
}


void rezolva() {
	int sol = 0;
	
	for (int i = 1; i <= n; i++) {
		s[i] = s1[i] - s2[i];
		
		if (s[i] == 0) sol = max(sol, i);

		if (m[s[i]]) {
			sol = max(sol, i - m[s[i]]);
		}
		else m[s[i]] = i;
	}

	cout << sol << '\n';
}


int main() {
	citeste();
	rezolva();
	return 0;
}