#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>
//#define int long long
//#define LL long long
#define double long double
//#define lf Lf
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define endl "\n"
#define PII pair<int,int>
#define Gheap priority_queue<int,vector<int>,greater<int>>
#define Lheap priority_queue<int>
#define MAXN 0x3f3f3f3f
#define MINN -0x3f3f3f3f
using namespace std;
//const int N=1e6+100,M=2*N;
//int e[N],w[M],h[M],ne[M],idx;

void solve()
{
    int n;cin>>n;
    char a[n+1];
    unordered_map<int,int> st;
    st[0]=st[n+1]=1;
    int ans=0,fg=0;
    for(int i=1;i<=n;i++)
    {
    	cin>>a[i];
    	if(a[i]=='1')
    	{
    		ans++;
    	}
    	if(a[i]=='0' and a[i-1]=='0' and i-1>=1) fg=1;
    }

    if(a[1] == '1' and a[n] =='1' and fg==0) ans++;

    cout<<ans<<endl;

}

int main()
{
    std::ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int tt=1,cnt=0;
    cin >> tt;
    while(tt--)
    {
    	cnt++;
    	if(cnt==94)
    	{
    		int num;
    		cin>>num;
    		string s;
    		cin>>s;
    		cout<<s<<endl;
    	}
    	solve();
    }

}
/*
10110101000

*/