1 #include<stdio.h>
2 #include<string.h>
3 #include<stdlib.h>
4 #include<math.h>
5 #include<algorithm>
6 using namespace std;
7 #define left 2
8 #define right 4
9 #define up 1
10 #define down 3
11 int n;
12 int a[1000];
13 int effort(int a,int b)
14 {
15 if(a==0)
16 {
17 return 2;
18 }
19 if(a==b)
20 {
21 return 1;
22 }
23 if((a==left&&b==right)||(a==right&&b==left))
24 {
25 return 4;
26 }
27 if((a==up&&b==down)||(a==down&&b==up))
28 {
29 return 4;
30 }
31 return 3;
32 }
33 int d[1000][5][5];
34 int found(int k,int leftfoot,int rightfoot)//当前要执行a[k]步伐
35 {
36 int temp1,temp2;
37 if(k==n-1)
38 {
39 temp1=effort(leftfoot,a[k]);
40 temp2=effort(rightfoot,a[k]);
41 return d[k][leftfoot][rightfoot]=temp1<temp2?temp1:temp2;;
42 }
43 if(d[k+1][leftfoot][a[k]]==-1)
44 {
45 found(k+1,leftfoot,a[k]);
46 }
47 if(d[k+1][a[k]][rightfoot]==-1)
48 {
49 found(k+1,a[k],rightfoot);
50 }
51 temp1=d[k+1][leftfoot][a[k]]+effort(rightfoot,a[k]);
52 temp2=d[k+1][a[k]][rightfoot]+effort(leftfoot,a[k]);
53 return d[k][leftfoot][rightfoot]=temp1>temp2?temp2:temp1;
54 }
55 void init()
56 {
57 int i,j,k;
58 for(i=0;i<n;i++)
59 {
60 for(j=0;j<5;j++)
61 {
62 for(k=0;k<5;k++)
63 {
64 d[i][j][k]=-1;
65 }
66 }
67 }
68 }
69 int main()
70 {
71 while(scanf("%d",&a[0]),a[0])
72 {
73 n=1;
74 while(scanf("%d",&a[n]),a[n])
75 {
76 n++;
77 }
78 init();
79 int ans=found(0,0,0);
80 printf("%d\n",ans);
81 }
82 return 0;
83 }
84 //56 ms
