//頑張って   #include <bits/stdc++.h>   #define ff first   #define ss second   #define ll long long   #define rep(i, n) for (int i = 0; i < n; i++)   using namespace std;   #define all(x) x.begin(), x.end()   void solve() {      int n;      cin >> n;      vector <int> a(n);      for (auto &i : a)         cin >> i;      int mxn = accumulate(all(a), 0);      vector <bool> dp(mxn + 1);      dp[0] = true;      for (int i = 0; i < n; i++) {         for (int j = mxn - a[i]; j >= 0; j--) {            if (dp[j] == true)               dp[a[i] + j] = true;         }      }      if ((mxn % 2 == 0 && !dp[mxn / 2]) || mxn % 2) {         cout <<  0 n ;         return;      }      while (true) {         for (int i = 0; i < n; i++) {            if (a[i] % 2 != 0) {               cout <<  1 n  << i + 1 <<   n ;               return;            }            a[i] /= 2;         }      }   }   int main() {   #ifndef ONLINE_JUDGE      freopen( inp.in ,  r , stdin);      freopen( outp.in ,  w , stdout);   #endif      ios::sync_with_stdio(false);   cin.tie(NULL);   cout.tie(NULL);      solve();      return 0;   }