#include <iostream>
#include <fstream>
#include <map>
using namespace std;
#define MAX 100010

map<long long, int> M;

long long a[MAX], b[MAX];

int main()
{
    int n, i, best;
    long long x;
    cin >> n;
    for(i = 1 ; i <= n ;i ++)
    {
        cin >> x;
        a[i] = a[i - 1] + x;
    }
    for(i = 1 ; i <= n ; i++)
    {
        cin >> x;
        b[i] = b[i - 1] + x;
    }
    for(i = 1 ; i <= n ; i++)
    {
        a[i] -= b[i];
    }
    M[0] = 0;
    best = 0;
    for(i = 1 ; i <= n ;i ++)
    {
        if(a[i] == 0)
        {
            best = max(best, i);
        }
        if(M[a[i]])
        {
            best = max(best, i - M[a[i]]);
        }
        else
            M[a[i]] = i;
    }
    cout << best << "\n";
}