#include <bits/stdc++.h>
using namespace std;
#define fastio (ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL))
typedef long long ll;
typedef long double lld;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
const int MAXSIZE = 2000000;
const long long INF = 1e9 + 5;
const double EPSILON = 1e-14;
const ll DIV = 2000003;
const long double pi = 3.14159265358979323846264338327950288419716939937510L;

int n;
int dp[1005][1005][1002][3];
int A[1005], B[1005];
int psum[1005];

pair<int, int> find(int l, int r, int tm, int rem)
{

    for (int i = l; i < r; i++)
    {
        if (A[i] <= rem + tm)
        {
            tm = 0;
            rem -= A[i] - tm;
        }
        else
        {
            return {i, rem};
        }
    }
    return {r, 0};
}

int solve(int l, int r, int tm, int c)
{
    if (r == n + 1)
        return psum[n] - psum[l - 1] - tm;

    int &ret = dp[l][r][tm][c];
    if (ret != -1)
        return ret;
    ret = INF;
    if (c == 1)
    {
        ret = min(ret, solve(l, r + 1, tm, 0));
    }
    auto p = find(l, r, tm, B[r]);
    ret = min(ret, solve(p.first, r + 1, p.second, 1) + B[r]);

    return ret;
}

int main()
{
    fastio;
    memset(dp, -1, sizeof dp);
    cin >> n;

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

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

    cout << solve(1, 1, 0, 0);

    return 0;
}

/tmp/ccwwG80t.o: in function `solve(int, int, int, int)':
answer.code:(.text+0x67): relocation truncated to fit: R_X86_64_PC32 against symbol `n' defined in .bss section in /tmp/ccwwG80t.o
/tmp/ccwwG80t.o: in function `main':
answer.code:(.text.startup+0x4e): relocation truncated to fit: R_X86_64_PC32 against symbol `n' defined in .bss section in /tmp/ccwwG80t.o
answer.code:(.text.startup+0x5c): relocation truncated to fit: R_X86_64_PC32 against symbol `n' defined in .bss section in /tmp/ccwwG80t.o
answer.code:(.text.startup+0x9d): relocation truncated to fit: R_X86_64_PC32 against symbol `n' defined in .bss section in /tmp/ccwwG80t.o
answer.code:(.text.startup+0xd4): relocation truncated to fit: R_X86_64_PC32 against symbol `n' defined in .bss section in /tmp/ccwwG80t.o
collect2: error: ld returned 1 exit status