Vasya has n days of vacations! So he decided to improve his IT skills and do sport. Vasya knows the following information about each of this n days: whether that gym opened and whether a contest was carried out in the Internet on that day. For the i-th day there are four options:

  1. on this day the gym is closed and the contest is not carried out; 
  2. on this day the gym is closed and the contest is carried out; 
  3. on this day the gym is open and the contest is not carried out; 
  4. on this day the gym is open and the contest is carried out. 



On each of days Vasya can either have a rest or write the contest (if it is carried out on this day), or do sport (if the gym is open on this day).

Find the minimum number of days on which Vasya will have a rest (it means, he will not do sport and write the contest at the same time). The only limitation that Vasya has — he does not want to do the same activity on two consecutive days: it means, he will not do sport on two consecutive days, and write the contest on two consecutive days.

Input

The first line contains a positive integer n (1 ≤ n ≤ 100) — the number of days of Vasya's vacations.

The second line contains the sequence of integers a1, a2, ..., an (0 ≤ ai ≤ 3) separated by space, where: 

  * ai equals 0, if on the i-th day of vacations the gym is closed and the contest is not carried out; 
  * ai equals 1, if on the i-th day of vacations the gym is closed, but the contest is carried out; 
  * ai equals 2, if on the i-th day of vacations the gym is open and the contest is not carried out; 
  * ai equals 3, if on the i-th day of vacations the gym is open and the contest is carried out.

Output

Print the minimum possible number of days on which Vasya will have a rest. Remember that Vasya refuses:

  * to do sport on any two consecutive days, 
  * to write the contest on any two consecutive days. 

Examples

Input

4
1 3 2 0


Output

2


Input

7
1 3 3 2 1 2 3


Output

0


Input

2
2 2


Output

1

Note

In the first test Vasya can write the contest on the day number 1 and do sport on the day number 3. Thus, he will have a rest for only 2 days.

In the second test Vasya should write contests on days number 1, 3, 5 and 7, in other days do sport. Thus, he will not have a rest for a single day.

In the third test Vasya can do sport either on a day number 1 or number 2. He can not do sport in two days, because it will be contrary to the his limitation. Thus, he will have a rest for only one day.

// import java.util.Vector;
import java.util.*;
import java.lang.Math;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
import javax.management.Query;

import org.w3c.dom.css.Counter;

import java.io.*;
import java.math.BigInteger;

public class Main {
    static int mod = 1000000007;

    /* ======================DSU===================== */
    static class dsu {
        static int parent[], n;// min[],value[];
        static long size[];

        dsu(int n) {
            parent = new int[n + 1];
            size = new long[n + 1];
            // min=new int[n+1];
            // value=new int[n+1];
            this.n = n;
            makeSet();
        }

        static void makeSet() {
            for (int i = 1; i <= n; i++) {
                parent[i] = i;
                size[i] = 1;
                // min[i]=i;
            }
        }

        static int find(int a) {
            if (parent[a] == a)
                return a;
            else {
                return parent[a] = find(parent[a]);// Path Compression
            }
        }

        static void union(int a, int b) {
            int setA = find(a);
            int setB = find(b);
            if (setA == setB)
                return;
            if (size[setA] >= size[setB]) {
                parent[setB] = setA;
                size[setA] += size[setB];
            } else {
                parent[setA] = setB;
                size[setB] += size[setA];
            }
        }
    }

    /* ======================================================== */
    static class Pair implements Comparator<Pair> {
        long x;
        long y;

        // Constructor
        public Pair(long x, long y) {
            this.x = x;
            this.y = y;
        }

        public Pair() {
        }

        @Override
        public int compare(Main.Pair o1, Main.Pair o2) {
            return ((int) (o1.x - o2.x));
        }
    }

    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

        int[] intArr(int n) {
            int res[] = new int[n];
            for (int i = 0; i < n; i++)
                res[i] = nextInt();
            return res;
        }

        long[] longArr(int n) {
            long res[] = new long[n];
            for (int i = 0; i < n; i++)
                res[i] = nextLong();
            return res;
        }
    }

    static FastReader f = new FastReader();
    static BufferedWriter w = new BufferedWriter(new OutputStreamWriter(System.out));

    static boolean isPrime(long n) {
        if (n <= 1)
            return false;
        if (n <= 3)
            return true;
        if (n % 2 == 0 || n % 3 == 0)
            return false;
        for (long i = 5; i * i <= n; i = i + 6)
            if (n % i == 0 || n % (i + 2) == 0)
                return false;
        return true;
    }

    static int LowerBound(int a[], int x) { // x is the target value or key
        int l = -1, r = a.length;
        while (l + 1 < r) {
            int m = (l + r) >>> 1;
            if (a[m] >= x)
                r = m;
            else
                l = m;
        }
        return r;
    }

    static int UpperBound(int a[], int x) {// x is the key or target value
        int l = -1, r = a.length;
        while (l + 1 < r) {
            int m = (l + r) >>> 1;
            if (a[m] <= x)
                l = m;
            else
                r = m;
        }
        return l + 1;
    }

    static long gcd(long a, long b) {
        if (a == 0)
            return b;
        return gcd(b % a, a);
    }

    static long lcm(long a, long b) {
        return (a * b) / gcd(a, b);
    }

    static long power(long x, long y, long p) {
        long res = 1;
        x = x % p;
        while (y > 0) {
            if (y % 2 == 1)
                res = (res * x) % p;
            y = y >> 1; // y = y/2
            x = (x * x) % p;
        }
        return res;
    }

    static long power(long x, long y) {
        long res = 1;
        while (y > 0) {
            if (y % 2 == 1)
                res = (res * x);
            y >>= 1;
            x = (x * x);
        }
        return res;
    }

    static int power(int x, int y) {
        int res = 1;
        while (y > 0) {
            if (y % 2 == 1)
                res = (res * x);
            y >>= 1;
            x = (x * x);
        }
        return res;
    }

    static int ceil(int x, int y) {
        return (x % y == 0 ? x / y : (x / y + 1));
    }

    static long ceil(long x, long y) {
        return (x % y == 0 ? x / y : (x / y + 1));
    }

    /*
     * ===========Modular Operations==================
     */
    static long modInverse(long n, long p) {
        return power(n, p - 2, p);
    }

    static long modAdd(long a, long b) {
        return (a % mod + b % mod) % mod;

    }

    static long modMul(long a, long b) {
        return ((a % mod) * (b % mod)) % mod;
    }

    static long nCrModPFermat(int n, int r) {
        long p = 1000000007;
        if (r == 0)
            return 1;
        long[] fac = new long[n + 1];
        fac[0] = 1;
        for (int i = 1; i <= n; i++)
            fac[i] = fac[i - 1] * i % p;
        return (fac[n] * modInverse(fac[r], p) % p * modInverse(fac[n - r], p) % p) % p;
    }

    /*
     * ===============================================
     */
    static List<Character> removeDup(ArrayList<Character> list) {
        List<Character> newList = list.stream().distinct().collect(Collectors.toList());
        return newList;
    }

    static void ruffleSort(long[] a) {
        int n = a.length;
        Random r = new Random();
        for (int i = 0; i < a.length; i++) {
            int oi = r.nextInt(n);
            long temp = a[i];
            a[i] = a[oi];
            a[oi] = temp;
        }
        Arrays.sort(a);
    }

    static void ruffleSort(int[] a) {
        int n = a.length;
        Random r = new Random();
        for (int i = 0; i < a.length; i++) {
            int oi = r.nextInt(n);
            int temp = a[i];
            a[i] = a[oi];
            a[oi] = temp;
        }
        Arrays.sort(a);
    }

    /*
     * ===========Dynamic prog Recur Section===========
     */

    static int dp[][];
    static ArrayList<ArrayList<Integer>> g;
    static int count = 0;
    //0 rest
    //1 gym
    //2 contest
    static int solve(int a[],int n,int last) {
        if(dp[last][n]!=-1){
            return dp[last][n];
        }
        if(n==0){
            return 0;
        }
        if(a[n-1]==0){
            dp[last][n]= 1+solve(a,n-1,0);
        }
        else if(a[n-1]==1){
            if(last==2){
                dp[last][n]= 1+solve(a,n-1,0);
            }else{
                dp[last][n]= solve(a,n-1,2);
            }
        }
        else if(a[n-1]==2){
            if(last==1){
                dp[last][n]= 1+solve(a,n-1,0);
            }else{
                dp[last][n]=solve(a,n-1,1);
            }
        }else{
            if(last==1){
                dp[last][n]= Math.min(solve(a,n-1,2),1+solve(a,n-1,0));
            }else if(last==2){
                dp[last][n]= Math.min(solve(a,n-1,1),1+solve(a,n-1,0));
            }else{
                dp[last][n]= Math.min(solve(a,n-1,1),solve(a,n-1,2));
            }
        }
        return dp[last][n];
    }

    static ArrayList<Long> bitMask(ArrayList<Long> ar, int n) {
        ArrayList<Long> ans = new ArrayList<>();
        for (int mask = 0; mask <= Math.pow(2, n) - 1; mask++) {
            long sum = 0;
            for (int i = 0; i < n; i++) {
                if (((1 << i) & mask) > 0) {
                    sum += ar.get(i);
                }
            }
            ans.add(sum);
        }
        return ans;
    }

    /*
     * ====================================Main=================================
     */
    public static void main(String args[]) throws Exception {
        // File file = new File("D:\\VS Code\\Java\\Output.txt");
        // FileWriter fw = new FileWriter("D:\\VS Code\\Java\\Output.txt");
        Random rand = new Random();
        int t = 1;
        // t = f.nextInt();
        int tc = 1;
        while (t-- != 0) {
            int n=f.nextInt();
            int a[]=new int[n];
            a=f.intArr(n);
            dp=new int[4][n+1];
            for(int i=0;i<4;i++)
                Arrays.fill(dp[i], -1);
            int p=solve(a,n,0);
            w.write(p+"\n");

        }
        w.flush();
    }
}