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#include <iostream>
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
#include <string>
#include <bitset>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <algorithm>
#include <sstream>
#include <stack>
#include <iomanip>
#include <assert.h>
using namespace std;
#define pb push_back
#define mp make_pair
typedef pair<int,int> pii;
typedef long long ll;
typedef double ld;
typedef vector<int> vi;
#define fi first
#define se second
#define fe first
#define FO(x) {freopen(#x".in","r",stdin);freopen(#x".out","w",stdout);}
#define Edg int M=0,fst[SZ],vb[SZ],nxt[SZ];void ad_de(int a,int b){++M;nxt[M]=fst[a];fst[a]=M;vb[M]=b;}void adde(int a,int b){ad_de(a,b);ad_de(b,a);}
#define Edgc int M=0,fst[SZ],vb[SZ],nxt[SZ],vc[SZ];void ad_de(int a,int b,int c){++M;nxt[M]=fst[a];fst[a]=M;vb[M]=b;vc[M]=c;}void adde(int a,int b,int c){ad_de(a,b,c);ad_de(b,a,c);}
#define es(x,e) (int e=fst[x];e;e=nxt[e])
#define esb(x,e,b) (int e=fst[x],b=vb[e];e;e=nxt[e],b=vb[e])
int T,n;
char s[233333];
void sol() {
	scanf("%d%s",&n,s+1);
	priority_queue<pii> oof;
	for(int i=1;i<=n;++i) if(s[i]=='0') {
		int p=i;
		while(s[i+1]=='0') ++i;
		int sd=(s[p-1]=='1')+(s[i+1]=='1');
		if(sd) oof.push(pii((i-p+1)*(3-sd),sd));
	}
	ll ans=0;
	for(int i=0;oof.size();++i) {
		auto w=oof.top(); oof.pop();
		if(w.se==1) w.fi/=2;
		if(i*w.se<w.fi) {
			ans+=i; w.fi-=i+1; --w.se;
			if(w.se) w.fi*=3-w.se,oof.push(w);
		}
		else ans+=w.fi;
	}
	for(int i=1;i<=n;++i) ans+=s[i]=='1';
	printf("%lld\n",ans);
}
int main()
{
	scanf("%d",&T);
	while(T--) sol();
}