include[HTML_REMOVED]

using namespace std;
int n;
struct node{
int num;
int t,r,vis;
}Node[103];
bool cmp(node a,node b){
return a.t[HTML_REMOVED]>n;
for(int i=1;i<=n;i){
cin>>Node[i].num;
Node[i].num*=10;
if(Node[i].num>0)
Node[i].r=1;
}
Node[1].t=0;
queue[HTML_REMOVED]q;
q.push(Node[1]);
Node[1].vis=1;
int ans=1;
while(!q.empty()){
node p=q.front();
q.pop();
vector[HTML_REMOVED]mmp;
for(int i=1;i<=n;i){
if(Node[i].vis==0){
int k=abs(abs(Node[i].num)-abs(p.num))/2;
if(Node[i].r!=p.r&&k>p.t){
if( (p.r==1&&abs(p.num)[HTML_REMOVED]abs(Node[i].num) )){
Node[i].t=k;Node[i].vis=1;
mmp.push_back(Node[i]);
ans++;
}

        }
    }
  }
  sort(mmp.begin(),mmp.end(),cmp);
  for(int i=0;i<mmp.size();i++){
    q.push(mmp[i]);
  }
}
cout<<ans;

}