1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <set>
#include <map>
#include <cstdio>
#include <sstream>
#include <iostream>
#include <cstring>
#define REP(i,x,v)for(int i=x;i<=v;i++)
#define REPD(i,x,v)for(int i=x;i>=v;i--)
#define FOR(i,v)for(int i=0;i<v;i++)
#define FOREACH(i,t) for (typeof(t.begin()) i=t.begin(); i!=t.end(); i++)
#define pb push_back
#define sz size()
#define mp make_pair
#define fi first
#define se second
#define ll long long
#define IN(x,y) ((y).find((x))!=(y).end())
#define LOLDBG
#ifdef LOLDBG
#define DBG(vari) cout<<#vari<<" = "<<vari<<endl;
#define DBG2(v1,v2) cout<<(v1)<<" - "<<(v2)<<endl;
#else
#define DBG(vari)
#define DBG2(v1,v2)
#endif
#define CZ(x) scanf("%d",&(x));
#define CZ2(x,y) scanf("%d%d",&(x),&(y));
#define ALL(x) (x).begin(),(x).end()
#include <random>
using namespace std;
typedef pair<int,int> pii;
typedef vector<int> vi;
template<typename T,typename TT> ostream &operator<<(ostream &s,pair<T,TT> t) {return s<<"("<<t.first<<","<<t.second<<")";}
template<typename T> ostream &operator<<(ostream &s,vector<T> t){s<<"{";FOR(i,t.size())s<<t[i]<<(i==t.size()-1?"":",");return s<<"}"<<endl; }


int main()
{
    int n,x;
    CZ(n);
    int cnt_ones = 0;
    FOR(i,n)
    {
        CZ(x);
        if (x==1) cnt_ones++;
    }
    if (cnt_ones>=2)printf("0\n");
    if (cnt_ones==1)printf("1\n");
    if (cnt_ones==0)printf("2\n");
    printf("2\n");
    printf("1 2\n");
    return 0;
}