import java.util.*;

public class _2342_1 {
    static int[][][] dp;
    static int[] inst;
    static int inst_num;
    static int[][] move_energy = {
        {1,2,2,2,2},
        {0,1,3,4,3},
        {0,3,1,3,4},
        {0,4,3,1,3},
        {0,3,4,3,1}
    };

    static int solve(int L, int R, int step) {
        if(step == inst_num) return 0;

        if(dp[step][L][R] == 0) {
            int target = inst[step];

            int moveLeft = solve(target, R, step+1) + move_energy[L][target];
            int moveRight = solve(L, target, step+1) + move_energy[R][target];

            dp[step][L][R] = Math.min(moveLeft, moveRight);
        }

        return dp[step][L][R];
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        inst = Arrays.stream(sc.nextLine().split(" "))
                           .mapToInt(Integer::parseInt)
                           .toArray();
        sc.close();

        inst_num = inst.length-1;
        dp = new int[inst_num][5][5];

        System.out.println(solve(0, 0, 0));
    }
}