//Author: Kevin
#include<bits/stdc++.h>
//#pragma GCC optimize("O2")
using namespace std;
#define ll long long
#define ull unsigned ll
#define pb emplace_back
#define mp make_pair
#define ALL(x) (x).begin(),(x).end()
#define rALL(x) (x).rbegin(),(x).rend()
#define srt(x) sort(ALL(x))
#define rev(x) reverse(ALL(x))
#define rsrt(x) sort(rALL(x))
#define sz(x) (int)(x.size())
#define inf 0x3f3f3f3f
#define pii pair<int,int>
#define lb(v,x) (int)(lower_bound(ALL(v),x)-v.begin())
#define ub(v,x) (int)(upper_bound(ALL(v),x)-v.begin())
#define uni(v) v.resize(unique(ALL(v))-v.begin())
#define longer __int128_t
void die(string S){puts(S.c_str());exit(0);}
bool flag[1001000];
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int t;
	cin>>t;
	while(t--)
	{
		int n;
		string s;
		cin>>n>>s;
		set<int> st;
		ll ans=0;
		for(int i=0;i<n;i++)
			if(s[i]=='1')
				st.insert(i);
		for(int i=0;i<n;i++)
			flag[i]=0;
		for(int i=n-1;i>=0;i--)
			if(!flag[i])
			{
				flag[i]=1;
				while(sz(st)&&*st.rbegin()>=i)
					st.erase(prev(st.end()));
				if(sz(st))
				{
					int x=*st.rbegin();
					st.erase(x);
					flag[x]=1;
					ans+=x+1;
				}
			}
		cout<<ans<<endl;
	}
	return 0;
}