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#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<queue>
#include<map>
#include<stack>
#include<cmath>
#include<set>
#include<bitset>
#include<complex>
#include<cstdlib>
#include<assert.h>
#define inc(i,l,r) for(int i=l;i<=r;i++)
#define dec(i,l,r) for(int i=l;i>=r;i--)
#define link(x) for(edge *j=h[x];j;j=j->next)
#define mem(a) memset(a,0,sizeof(a))
#define ll long long
#define eps 1e-8
#define succ(x) (1<<x)
#define lowbit(x) (x&(-x))
#define mid (x+y>>1)
#define sqr(x) ((x)*(x))
#define NM 524288
#define nm 200005
using namespace std;
const double pi=acos(-1);
const ll inf=99993601;
ll read(){
ll x=0,f=1;char ch=getchar();
while(!isdigit(ch)){if(ch=='-')f=-1;ch=getchar();}
while(isdigit(ch))x=x*10+ch-'0',ch=getchar();
return f*x;
}
inline void reduce(ll&x){x+=x>>63&inf;}
int n,ans,m,_t,s,cnt[NM];
ll a[3][NM],f[NM];
void fwt(ll*a){
for(int k=1;k<n;k<<=1)
for(int i=0;i<n;i+=k<<1)
for(int j=0;j<k;j++){
ll x=a[i+j],y=a[i+j+k];
reduce(a[i+j]=x+y-inf);reduce(a[i+j+k]=x-y);
}
}
int main(){
m=read();inc(i,1,m)_t=read(),f[_t]++,s^=_t;
n=1<<19;
inc(i,0,n-1)cnt[i]=(__builtin_popcount(i&s)&1)?-1:1;
a[0][0]=1;
fwt(f);fwt(a[0]);
do{
ll s=0;
inc(i,0,n-1)s+=a[ans%3][i]*cnt[i],s%=inf;
if(s)break;
ans++;
inc(i,0,n-1)a[ans%3][i]=a[(ans+2)%3][i]*f[i]%inf;
if(ans>1)inc(i,0,n-1)reduce(a[ans%3][i]-=(m-ans+2)*a[(ans+1)%3][i]%inf);
}while(ans<m);
printf("%d\n",m-ans);
return 0;
}
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