#include<cstdio>
#include<cstring>
using namespace std;
typedef long long ll;
inline ll read(){
	ll x=0;
	int f=0,ch=0;
	while(ch<48||ch>57) f=(ch=='-'),ch=getchar();
	while(ch>47&&ch<58) x=(x<<3)+(x<<1)+(ch&15),ch=getchar();
	return f?-x:x;
}
inline void write(ll x,char end='\n'){
	if(x==0){
		putchar('0');
		putchar(end);
		return;
	}
	if(x<0) putchar('-'),x=-x;
	int ch[40]={0},cnt=0;
	while(x){
		ch[cnt++]=(int)(x%10);
		x/=10;
	}
	while(cnt--) putchar(ch[cnt]+48);
	putchar(end);
}
const int N=2e5+5;
int n;
char s[N];
inline void solve(){
    n=read();
    scanf("%s",s+1);
    int cnt=0;
    for(int i=1;i<=n;++i) cnt+=s[i]=='1';
    if(s[1]=='0'||s[n]=='0'){
        write(cnt);
        return;
    }
    for(int i=1;i<n;++i){
        if(s[i]=='0'&&s[i+1]=='0'){
            write(cnt);
            return;
        }
    }
    write(cnt+1);
}
int main(){
    int T=read();
    while(T--) solve();
    return 0;
}