#include <bits/stdc++.h>

using namespace std; const int maxn = 2e5 + 5; typedef long long ll;

int n, B[maxn], C[maxn];

ll V[maxn]; int D[maxn], m;


int main()
{
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) scanf("%d", B + i);
    for (int i = 1; i <= n; i++) scanf("%d", C + i);
    for (int i = 1; i <= n; i++) if (B[i] < C[i])
    {
        ++m;
        V[m] = (C[i] - B[i]) * 2 + V[m - 1];
        D[m] = B[i];
    }
    int U = max(B[n], C[n]);
    ll ans = V[m];
    for (int i = m; i; i--) ans = min(ans, U - D[i] + V[i - 1]);
    printf("%lld\n", ans + U);
}