#include<bits/stdc++.h>
#define ll long long
#define all(a) (a).begin(),(a).end()
using namespace std;

const int maxn = 2e5 + 10;

ll n;
ll a[maxn];
void work1()
{
    ll cnt0=0;
    for (int i=2; i<=n; i++)
        if (a[i]==0) cnt0++;
    if (cnt0==0) { cout << "1\n"; return; }
    if (cnt0>=2) { cout << "2\n"; return; }
    if (cnt0==1 && a[2]==0) { cout << "1\n"; return; }
    else { cout << "2\n"; return; }
}
void work2()
{
    ll q=n;
    ll cnt0=0;
    while (a[q]==0 && q>=2)
    {
        cnt0++;
        q--;
    }
    if (q==1) cout << cnt0 << "\n";
    else cout << cnt0+1 << "\n";
}
void solve()
{
    cin >> n;
    for (int i=2; i<=n; i++) cin >> a[i];

    if (a[n]==1) work1();
    else work2();
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);cout.tie(nullptr);
    int t = 1;
    //cin >> t;
    while(t--) solve();
    return 0;
}