#include <bits/stdc++.h>

using namespace std;

//ifstream fin("default.in");
//ofstream fout("default.out");

const int MAX = 5e5 + 5;

long long a[MAX], b[MAX], v[MAX];
int n;
unordered_map<long long, vector<int>> sums;
vector<int> keys;

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

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

    long long currentSum = 0;
    sums[0].push_back(0);
    keys.push_back(0);
    for (int i = 1; i <= n; i++) {
        currentSum += v[i];
        if (!sums.count(currentSum))
            keys.push_back(currentSum);
        sums[currentSum].push_back(i);
    }

    int sola = -1, solb = -1;
    for (auto key : keys) {
        //cerr << "SUM = " << key << endl;
        if (sums[key].size() == 1)
            continue;

        int minn = n;
        int maxx = 0;

        for (auto ind : sums[key]) {
            //cerr << ind << ' ';
            minn = min(ind, minn);
            maxx = max(ind, maxx);
        }
        //cerr << endl;

        if (maxx - minn >= solb - sola) {
            sola = minn;
            solb = maxx;
        }
    }
    cout << (sola == -1 ? 0 : solb - sola);
    return 0;
}