#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<int,int> pii;
typedef vector<int> vii;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef unordered_map<int,int> umap;
typedef long double ld;
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define popcount __builtin_popcount
#define case cout<<"Case "<<__testcase-testcase<<": ";
#define endl '\n'
#define inf 1e9

ll a[100500],b[100500];

ll gcd(ll a,ll b, ll& x,ll& y)
{
    if(b==0)
    {
        x=1,y=0;
        return a;
    }
    ll x1,y1;
    ll d=gcd(b,a%b,x1,y1);
    x=y1;
    y=x1-y1*(a/b);
    return d;
}
bool f(ll a,ll b,ll c,ll& x0,ll&y0, ll& g)
{
    g=gcd(abs(a),abs(b),x0,y0);
    if(c%g)
        return false;
    x0*=c/g;
    y0*=c/g;
    if(a<0)x0=-x0;
    if(b<0)y0=-y0;
    return true;
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    int testcase=1;
    //cin>>testcase;
    int __testcase=testcase;
    while(testcase--){
        int n,i;
        cin>>n;
        ll x=n-1,y=1,sum=0,g;
        ll z=-1;
        if(n%2)
            z=1;
        b[0]=1*z;

        for(int i=0;i<n;i++){
            cin>>a[i];
            if(i!=0)
            {
                b[i]=(b[i-1]*x*(-1))/y;
                x--;
                y++;
            }
            sum+=a[i]*b[i];
        }

        ll cnt=0,m=235813,l=-100000,r=100000;
        for(i=0;i<n;i++)
        {
            f(b[i],-m,-(sum-(b[i]*a[i])),x,y,g);
            x=abs(x)%m;
            if((x<=r&&x!=a[i])||(x-m>=l&&x-m!=a[i]))
                cnt++;

        }

        cout<<cnt<<endl;

    }
}