#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<=b;i++)
typedef long long ll;
typedef double db;
const int maxn = 5e5 + 5;
const int mod = 1e9 + 7;

ll a[maxn], dp[maxn][5];

int main(){
    int n;
    scanf("%d", &n);
    rep(i, 1, n)
        scanf("%lld", &a[i]);
    rep(i, 1, n){
        dp[i][0] = dp[i-1][0];
        rep(j, 1, 4)
            dp[i][j] = min(dp[i][j-1], dp[i-1][j]);
        dp[i][0] += a[i]; dp[i][4] += a[i];
        dp[i][1] += a[i] == 0 ? 2 : (a[i] & 1);
        dp[i][3] += a[i] == 0 ? 2 : (a[i] & 1);
        dp[i][2] += a[i] & 1 ^ 1;
    }
    ll ans = dp[n][0];
    rep(i, 1, 4)
        ans = min(ans, dp[n][i]);
    printf("%lld\n", ans);
    return 0;
}
