Petya loves football very much, especially when his parents aren't home. Each morning he comes to the yard, gathers his friends and they play all day. From time to time they have a break to have some food or do some chores (for example, water the flowers).

The key in football is to divide into teams fairly before the game begins. There are *n* boys playing football in the yard (including Petya), each boy's football playing skill is expressed with a non-negative characteristic *a*<sub class="lower-index">*i*</sub> (the larger it is, the better the boy plays). 

Let's denote the number of players in the first team as *x*, the number of players in the second team as *y*, the individual numbers of boys who play for the first team as *p*<sub class="lower-index">*i*</sub> and the individual numbers of boys who play for the second team as *q*<sub class="lower-index">*i*</sub>. Division *n* boys into two teams is considered fair if three conditions are fulfilled:
 -  Each boy plays for exactly one team (*x* + *y* = *n*). -  The sizes of teams differ in no more than one (|*x* - *y*| ≤ 1). -  The total football playing skills for two teams differ in no more than by the value of skill the best player in the yard has. More formally: <center class="tex-equation"><img align="middle" class="tex-formula" src="https://espresso.codeforces.com/b00349240b8889b3cc16970c552a5a2581cf0801.png" style="max-width: 100.0%;max-height: 100.0%;"/></center>
Your task is to help guys divide into two teams fairly. It is guaranteed that a fair division into two teams always exists.
The first line contains the only integer *n* (2 ≤ *n* ≤ 10<sup class="upper-index">5</sup>) which represents the number of guys in the yard. The next line contains *n* positive space-separated integers, *a*<sub class="lower-index">*i*</sub> (1 ≤ *a*<sub class="lower-index">*i*</sub> ≤ 10<sup class="upper-index">4</sup>), the *i*-th number represents the *i*-th boy's playing skills.
3
1 2 1
2
1 2 
1
3 
5
2 3 3 1 1
3
4 1 3 
2
5 2 
10
2 2 2 2 2 2 2 1 2 2
5
8 2 4 6 9 
5
1 3 5 7 10 
10
2 3 3 1 3 1 1 1 2 2
5
4 7 1 10 3 
5
6 8 9 2 5 
10
2 3 2 3 3 1 1 3 1 1
5
6 9 1 2 5 
5
7 10 3 4 8 
11
1 3 1 2 1 2 2 2 1 1 1
6
1 5 10 4 7 2 
5
3 9 11 6 8 
11
54 83 96 75 33 27 36 35 26 22 77
6
10 6 8 1 11 3 
5
9 5 7 4 2 
11
1 1 1 1 1 1 1 1 1 1 1
6
1 3 5 7 9 11 
5
2 4 6 8 10 
2
1 1
1
1 
1
2 
2
35 36
1
1 
1
2 
25
1 2 2 1 2 2 2 2 2 1 1 2 2 2 2 2 1 2 2 2 1 1 2 2 1
13
1 10 17 22 2 5 7 9 13 15 18 20 24 
12
4 11 21 25 3 6 8 12 14 16 19 23 
27
2 1 1 3 1 2 1 1 3 2 3 1 3 2 1 3 2 3 2 1 2 3 2 2 1 2 1
14
2 5 8 15 25 1 10 17 21 24 4 11 16 22 
13
3 7 12 20 27 6 14 19 23 26 9 13 18 
30
2 2 2 3 4 3 4 4 3 2 3 2 2 4 1 4 2 4 2 2 1 4 3 2 1 3 1 1 4 3
15
15 25 28 2 10 13 19 24 6 11 26 5 8 16 22 
15
21 27 1 3 12 17 20 4 9 23 30 7 14 18 29 
100
3 4 8 10 8 6 4 3 7 7 6 2 3 1 3 10 1 7 9 3 5 5 2 6 2 9 1 7 4 2 4 1 6 1 7 10 2 5 3 7 6 4 6 2 8 8 8 6 6 10 3 7 4 3 4 1 7 9 3 6 3 6 1 4 9 3 8 1 10 1 4 10 7 7 9 5 3 8 10 2 1 10 8 7 10 8 5 3 1 2 1 10 6 1 5 3 3 5 7 2
50
14 27 34 63 70 89 94 23 30 44 90 1 13 20 51 59 66 88 97 7 31 53 64 21 38 87 98 11 33 43 49 62 9 18 35 52 73 84 3 45 47 78 86 26 65 4 36 69 79 85 
50
17 32 56 68 81 91 12 25 37 80 100 8 15 39 54 61 77 96 2 29 42 55 71 22 76 95 6 24 41 48 60 93 10 28 40 57 74 99 5 46 67 83 19 58 75 16 50 72 82 92 
100
85 50 17 89 65 89 5 20 86 26 16 21 85 14 44 31 87 31 6 2 48 67 8 80 79 1 48 36 97 1 5 30 79 50 78 12 2 55 76 100 54 40 26 81 97 96 68 56 87 14 51 17 54 37 52 33 69 62 38 63 74 15 62 78 9 19 67 2 60 58 93 60 18 96 55 48 34 7 79 82 32 58 90 67 20 50 27 15 7 89 98 10 11 15 99 49 4 51 77 52
50
26 20 68 7 19 89 65 93 14 62 94 3 73 8 12 43 32 18 56 28 59 15 27 96 34 51 55 41 38 48 82 72 63 5 67 47 61 99 64 33 24 80 13 17 4 90 71 74 45 95 
50
30 37 97 31 78 23 92 36 50 88 11 52 66 85 10 87 16 81 77 54 42 21 76 2 86 98 100 53 75 70 69 58 60 22 84 57 39 35 25 79 44 1 9 49 6 83 46 29 91 40 
100
2382 7572 9578 1364 2325 2929 7670 5574 2836 2440 6553 1751 929 8785 6894 9373 9308 7338 6380 9541 9951 6785 8993 9942 5087 7544 6582 7139 8458 7424 9759 8199 9464 8817 7625 6200 4955 9373 9500 3062 849 4210 9337 5466 2190 8150 4971 3145 869 5675 1975 161 1998 378 5229 9000 8958 761 358 434 7636 8295 4406 73 375 812 2473 3652 9067 3052 5287 2850 6987 5442 2625 8894 8733 791 9763 5258 8259 9530 2050 7334 2118 2726 8221 5527 8827 1585 8334 8898 6399 6217 7400 2576 5164 9063 6247 9433
50
64 59 54 58 66 49 4 12 53 85 5 10 96 86 72 70 48 42 37 25 55 71 44 8 36 99 93 27 15 28 18 30 2 61 46 87 62 29 14 89 92 23 98 17 16 100 39 20 31 24 
50
52 65 60 78 41 13 90 51 83 45 1 67 75 9 6 40 68 63 47 97 80 74 88 50 94 19 11 22 73 84 95 26 35 7 32 81 91 77 34 76 57 56 69 43 38 33 82 3 79 21 
3
1 2 3
2
1 3 
1
2 
3
10 10 10
2
1 3 
1
2 
3
5 10 10
2
1 3 
1
2 
5
6 1 1 1 1
3
2 4 1 
2
3 5 
5
1 100 2 200 3
3
1 5 4 
2
3 2 
n=int(intput())
a=list(map(int,input().split()))

p,q=[],[]
d={i:a[i] for i in range(n)}

maxi=(sum(a)+max(a))//2
sumi=0
a.sort()
for i in range(n):
    sumi+=a[i]
    if sumi<=maxi:
        index=list(d.values()).index(a[i])
        p.append(index+1)
        d[index]=-1
    else:
        break
for i,j in d.items():
    if j!=-1:
        q.append(i)
print(len(p))
print(*p)
print(len(q))
print(*q)