#include "bits/stdc++.h"
using namespace std;

#define ffor(n) for(int i = 0; i < n; i++)
#define fffor(n) for(int j = 0; j < n; j++)
#define uwu ios::sync_with_stdio(false);cin.tie(NULL);
#pragma GCC optimize("Ofast")

const int INF = 1e9 + 7;
const long long INF2 = 1e17;

int main(void) {
	uwu
	
	int n; cin >> n;
	vector <int> v(n);
	ffor(n) cin >> v[i];
	
	vector <bool> visited(1e5 + 5);
	int total = 0;
	for(int x: v) total += x;
	auto possible = [&] (int pos) {
		int sum = total;
		if (pos != -1) sum -= v[pos];
		if (sum % 2 == 1) return false;
		sum /= 2;
		
		fill(visited.begin(), visited.end(), 0);
		visited[0] = true;
		for(int i = 0; i < n; i++) {
			if (i == pos) continue;
			int x = v[i];
			for(int j = (int)visited.size(); j >= 0; j--) {
				if (j + x >= (int)visited.size()) continue;
				if (visited[j]) visited[j + x] = true;
			}
		}
		return (visited[sum] == true);
	};
	
	if (possible(-1) == false) cout << 0 << '\n';
	else {
		for(int i = 0; i < n; i++) {
			if (possible(i) == false) {
				cout << 1 << '\n' << i + 1 << '\n';
				break;
			}
		}
	}
}
/*
C:\Users\kenne\OneDrive\Desktop\competitive_programming\main.cpp
*/
