/*
Hey  why peeping here -_'_- ?
I believe on myself and I will achieve
this->author = Fuad Ashraful Mehmet, CSE ,University of Asia Pacific
Todo:
https://www.youtube.com/watch?v=VoTUc-1qIT8&ab_channel=TipsJhankarGaane
https://codeforces.com/problemset/page/1?tags=1500-1900
*/
#include <bits/stdc++.h>
#define forn(i, n) for (int i = 0; i < int(n); ++i)
#define all(o) (o).begin(), (o).end()
#define rall(o) (o).rbegin(), (o).rend()
#define sz(o) (o).size()
#define FAST_IO  ios_base::sync_with_stdio(0); cin.tie(nullptr); cout.tie(nullptr);
#define dbg(o) cerr << "at " << __LINE__ << " response = " << o << endl;
#define dbgA(a,L,R) cerr<<#a<<"=[";for(int i=L;i<=R;i++) cerr<<a[i]<<(i==R?"]\n":" ");
#define dbgV(O) cerr << #O << "=["; for (auto o : O) cerr << o << ", "; cerr << "E]\n";
#define pb push_back
using namespace std;
using pii = pair<int, int>;
typedef long long ll;
int  m,tc=1,q,cs=1,len,n,k;
const int N=2e5+5;
int a[105];
bool dp[N];
int sum;

int min_step(int num)
{
	return num&1?0:1+min_step(num>>1);
}
void solve()
{
	cin>>n;
	sum=0;
	for(int i=1;i<=n;++i)
	{
		cin>>a[i];
		sum+=a[i];
	}
	if(sum&1)
	{
		cout<<"0\n";
		return;
	}
	sum>>=1;
	dp[0]=true;

	for(int i=1;i<=n;++i)
	{
		for(int j=sum-a[i];j>=0;--j)
		{
			dp[j+a[i]]|=dp[j];
		}
	}

	if(!dp[sum])
	{
		cout<<"0\n";
		return;
	}

	int ans=2e9,idx=0;
	for(int i=1;i<=n;++i)
	{
		if(min_step(a[i])<ans)
		{
			ans=min_step(a[i]);
			idx=i;
		}
	}

	cout<<"1\n"<<idx<<'\n';
	return;
	
}
int main()
{
	FAST_IO
	//cout<<setprecision(20)<<fixed;
	//cin>>tc;
	while(tc--)
	{
		solve();
	}
	return 0;
}