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#include<cstdio>
#include<cmath>
#include<vector>
#include<iostream>
#include<string> 
#include<algorithm>

using namespace std;

int main(){
    int n,t;
    char c;
    scanf("%d", &t);
    for( int i =0; i < t; i++){
        scanf("%d", &n);
        char cities[n];
        scanf("%s", cities);
        vector<pair<int,int> > tmp;
        int good = 0;
        char city = '0';
        bool prev_good = false;
        bool any_bad_before = false;
    
        for( int j=0; j < n; j++){
            city = cities[j];
            if (city == '0'){
                good++;
                prev_good = true;
                if ( j == n-1 ){
                    if ( any_bad_before == false ){
                        
                        tmp.push_back(make_pair(good, 0));
                    }
                    else{
                        tmp.push_back(make_pair(good, 1));
                    }
                }
                continue;
            }
            else{
                if (prev_good == true){
                
                    prev_good = false;
                    if ( any_bad_before == false){
                        tmp.push_back(make_pair(good, 1));
                        good=0;
                        any_bad_before = true;
                    }
                    else{
                        tmp.push_back(make_pair(good, 2));
                        good=0;
                    }
                }
                else{
                   any_bad_before = true;
                   continue;
                }
            }
            
            
        } 
        if (tmp.size() == 1 && tmp[0].second == 0){
            printf("%d\n", 0);
            continue;
        }

        sort(tmp.begin(), tmp.end(), [](auto a, auto b) { return float(a.first) / a.second > float(b.first) / b.second; });
        int day = 0;
        long long int result = 0;
	for( auto g : tmp){

	    if ( g.first  > day * g.second){
	        if (g.second == 0){
	            result += g.first;
	        }
	        else if(g.second == 1){
	            result += g.first - day;
	            day++;
	        }
	        else{
	            result += 1;
	            if (g.first - 2 *day  > 2){
	               result += g.first - 2 *day -2;
	               day++;
	            }
	            day++;
	        }
	    }
	    else
	        break;
           
        }
        printf("%d\n", n -result);
		    
    }
    return 0;
}