#include<bits/stdc++.h>
using namespace std;
#define int long long
#define f first
#define s second
#define mp make_pair
#define eb emplace_back
#define pb push_back
typedef pair<int,int> pii;

int32_t main() {
    ios_base::sync_with_stdio(false);cin.tie(0);
    int n;
    cin>>n;
    int arr[n+5];
    for(int i=2;i<=n;i++){
        cin>>arr[i];
    }
    bool fc=1;
    for(int i=3;i<=n;i++){
        if(arr[i]==0)fc=0;
    }
    if(fc){
        cout<<"1\n";
        return 0;
    }
    int s=0;
    for(int i=n;i>=3;i--){
        if(arr[i]==0)s++;
        else break;
    }
    cout<<max(2ll,min(s+1,n-1));
}