#include <bits/stdc++.h>
using namespace std;
int a[100010];
int b[100010];
long long dp[100010][2];
int main() {
  int n;
  cin >> n;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
  }
  for (int i = 1; i <= n; ++i) {
    cin >> b[i];
  }
  dp[1][0] = a[1];
  dp[1][1] = b[1];
  long long ans = max(a[1], b[1]);
  for (int i = 2; i <= n; ++i) {
    dp[i][0] = max(dp[i - 1][1], max(dp[i - 2][0], dp[i - 2][1])) + a[i];
    dp[i][1] = max(dp[i - 1][0], max(dp[i - 2][0], dp[i - 2][1])) + b[i];
    ans = max(ans, dp[i][0]);
    ans = max(ans, dp[i][1]);
  }
  cout << ans << endl;
}
