#include <bits/stdc++.h>   using namespace std;       #define fastIO ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);   #define endl   n    #define lli long long int   #define ld long double   #define p_b push_back   #define m_p make_pair   #define fs first   #define sc second   #define sz(x) ((lli)x.size())   #define all(x) x.begin(),x.end()   const lli mod = 1e9 + 7;   const lli N = 1e6 + 5;   /*****************************************************/   lli t,n,m,a[N]={0},target;   bool dp[105][200005],vis[105][200005];   lli F(lli idx,lli ss)   {       if(vis[idx][ss])           return dp[idx][ss];       vis[idx][ss]=true;       if(idx>n)       {           if(ss==target)               return dp[idx][ss]=true;           return dp[idx][ss]=false;       }       bool ret=F(idx+1,ss),ret1=F(idx+1,ss+a[idx]);       if(ret || ret1)           return dp[idx][ss]=true;       return dp[idx][ss]=false;   }   int main()   {       fastIO       lli i,j,k,x,y;       lli ss=0;       cin>>n;       for(i=1;i<=n;i++)       {           cin>>a[i];           ss+=a[i];       }       if(ss%2!=0)       {           cout<< 0 ;           return 0;       }       target=ss/2;       memset(vis,false,sizeof vis);       memset(dp,false,sizeof dp);       if(F(1,0)==false)       {           cout<< 0 ;           return 0;       }       while(1)       {           for(i=1;i<=n;i++)           {               if(a[i]%2!=0)               {                   cout<< 1 n <<i;                   return 0;               }               a[i]/=2;           }        }              // cerr<<   n  <<  Time elapsed :  << clock() * 1000.0 / CLOCKS_PER_SEC <<   ms n  ;       return 0;   }