#include<bits/stdc++.h>
#define int long long
#define endl '\n'
#define PB push_back
#define pii pair<int, int>
using namespace std;
const int N = 2e5 + 5;
const int INF = 1e18;
int a[N];
void solve(){
    int n;
    cin >> n;
    bool one = 1, zero = 1;
    for(int i=1; i<n; i++){
        cin >> a[i];
        if(i > 1){
            if(a[i]) zero = 0;
            if(!a[i]) one = 0;
        }
    }
    a[1] = 1;

    if(zero){
        cout << n - 1 << endl;
        return;
    }
    if(one){
        cout << 1 << endl;
        return;
    }

    for(int i=n-1; i>0; i--){
        if(a[i]){
            if(i == n-1) cout << 2 << endl;
            else cout << n - i << endl;
            break;
        }
    }
}
signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    int T = 1;
    // cin >> T;
    while(T--){
        solve();
    }
}