#include <bits/stdc++.h>
using namespace std;
// type
typedef long long ll;
typedef long double ld;
// loop
//#define For(i, l, r, x) for (int i = l; i < r; i+=x)
//#define ForE(i, l, r, x) for (int i = l; i <= r; i+=x)
//#define Ford(i, r, l) for (int i = r; i > l; i--)
//#define FordE(i, r, l) for (int i = r; i >= l; i--)
//#define Fora(i, a) for (auto i : a)
// I/O
#define FAST_IO std::ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
//#define PrintV(a) Fora(ii, a) cout << ii << ' '; cout << rl;
//#define PrintVl(a) Fora(ii, a) cout << ii << rl;
//#define PrintA(a, l, r) for (int ii = l; ii <= r; ii++) cout << a[ii] << ' '; cout << rl;
//#define PrintAl(a, l, r) for (int ii = l; ii <= r; ii++) cout << a[ii] << rl;
//#define Ptest(x) return cout << x, 0;
#define setpre(n) fixed << setprecision(n)
// pair
#define F first
#define S second
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pdd pair<ld, ld>
// vector & !!?(string)
#define eb emplace_back
#define pb push_back
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define sz(a) a.size()
#define len(a) a.length()
// geometry calc
#define pi acos(-1.0)
#define g_sin(a) sin(a*pi/180)
#define g_cos(a) cos(a*pi/180)
#define g_tan(a) tan(a*pi/180)
// set val
#define ms0(a) memset(a, 0, sizeof(a));
#define ms1(a) memset(a, 1, sizeof(a));
#define msn1(a) memset(a, -1, sizeof(a));
#define msinf(a) memset(a, 0x3f3f3f, sizeof(a));
// constant
const int mod1 = 998244353, mod = 1e9+7;
const int MAX_N = 100005, MAX_M = 200010;
// code
//#define int long long
int a[3][MAX_N], n, re[3][MAX_N], dp[3][MAX_N];
void Solve() {
cin >> n;
for (int i = 0; i < 2; i++){
for (int j = 1; j <= n; j++){
cin >> a[i][j];
}
}
for (int i = 1; i <= n; i++){
a[0][i] += a[0][i-1];
a[1][i] += a[1][i-1];
a[2][i] = a[1][i] + a[0][i];
}
for (int t = 0; t < 3; t ++){
map<int, int> idx;
for (int i = 0; i <= n; i++){
if (idx.count(a[t][i])){
re[t][i] = idx[a[t][i]];
}else{
re[t][i] = -1;
}
idx[a[t][i]] = i;
}
}
for (int t = 0; t < 2; t ++){
for (int i = 1; i <= n; i++){
dp[t][i] = dp[t][i-1];
if (re[t][i] != -1)
dp[t][i] = max(dp[t][i], 1 + dp[t][re[t][i]]);
dp[2][i] += dp[t][i];
}
}
for (int i = 1; i <= n; i++){
dp[2][i] = max(dp[2][i-1], dp[2][i]);
if (re[2][i] != -1)
dp[2][i] = max(dp[2][i], 1 + dp[2][re[2][i]]);
}
/*
for (int i = 0; i < 3; i++){
for (int j = 1; j <= n; j++)
cout << dp[i][j] << ' ';
cout << endl;
}
*/
cout << dp[2][n];
}
signed main(){
FAST_IO;
int TC = 1;
//cin >> TC;
while(TC--) Solve();
return 0;
}
