#include<bits/stdc++.h>
using namespace std;

#define int long long
typedef vector<int>vint;
typedef pair<int,int>pint;
typedef vector<pint>vpint;
#define rep(i,n) for(int i=0;i<(n);i++)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
#define all(v) (v).begin(),(v).end()
#define each(it,v) for(__typeof((v).begin()) it=(v).begin();it!=(v).end();it++)
#define pb push_back
#define fi first
#define se second
template<typename A,typename B>inline void chmin(A &a,B b){if(a>b)a=b;}
template<typename A,typename B>inline void chmax(A &a,B b){if(a<b)a=b;}

int N;
int A[111111];
int deg[111111];

signed main(){
    cin>>N;
    rep(i,N)cin>>A[i];
    rep(i,N)deg[(i+A[i])%N]++;

    queue<int>que;
    rep(i,N)if(deg[i]==0)que.push(i);
    while(que.size()){
        int v=que.front();
        que.pop();
        if(--deg[(v+A[v])%N]==0)que.push((v+A[v])%N);
    }
    int ans=0;
    rep(i,N)if(deg[i])ans++;
    cout<<ans<<endl;
    return 0;
}