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//Krzysztof Pieprzak
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
typedef unsigned int uint;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int,int> pii;
typedef pair<long long, long long> pll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;

#define Size(x) (int)x.size()
#define VAR(v,n) auto v = (n)
#define FOR(i,a,b) for(VAR(i,a); i < (b); ++i)
#define FORE(i,a,b) for(VAR(i,a); i <= (b); ++i)
#define FORREV(i,a,b) for(VAR(i,b); i >= (a); --i)
#define FORSTEP(i,a,b,step) for(VAR(i,a); i < (b); i += (step))
#define FOREACH(i,c) for(auto i : (c))
#define FOREACHS(i,c,n) for(VAR(i,&(c)[0]); i-(c)<(n); ++i)
#define ALL(x) x.begin(),x.end()
#define CLEAR(t) memset(t, 0, sizeof(t))
#define F first
#define S second
#define MP make_pair
#define PUB push_back
#define POB pop_back
#define pieprzu ios_base::sync_with_stdio(0);

#define debugOn 0
#define debug(a,b) if (debugOn) cout << a << ": " << b << endl;

const int    INF = 1000000001;
const double EPS = 10e-9;

const int MAXN = 100000;

int n;

char t[MAXN + 5];
vi oneSided;
vi twoSided;

void cleanup() {
    oneSided.clear();
    twoSided.clear();
}

void read() {
    scanf("%d", &n);
    scanf("%s", t);

    int curLen = 0;
    bool isOneSided = true;
    int infected = 0;
    FOR (i, 0, n) {
        if (t[i] == '1') {
            if (curLen > 0) {
                if (isOneSided) {
                    oneSided.PUB(curLen);
                } else {
                    twoSided.PUB(curLen);
                }
            }

            curLen = 0;
            isOneSided = false;
        } else {
            ++curLen;
        }
    }

    if (curLen > 0) {
        oneSided.PUB(curLen);
    }

    sort(ALL(oneSided));
    sort(ALL(twoSided));
}

int takeTwoSided(int cured, int rounds) {
    int current = 0;
    FORREV (i, 0, Size(twoSided) - 1) {
        current = twoSided[i] - 2 * rounds;

        if (current <= 0) {
            break;
        }

        cured += max(1, current - 1);
        rounds += 2;
    }
    return n - cured;
}

int takeNoOneSided() {
    return takeTwoSided(0, 0);
}

int takeOneOneSided() {
    int cured = oneSided[Size(oneSided) - 1];
    return takeTwoSided(cured, 1);
}

int takeTwoOneSided() {
    int cured = oneSided[0] + oneSided[1] - 1;
    return takeTwoSided(cured, 2);
}

void rob(int test) {
    cleanup();
    read();

    int result = takeNoOneSided();
    debug("no 1 sided", result);
    if (Size(oneSided) == 1) {
        result = min(result, takeOneOneSided());
        debug("1 1 sided", result);
    } else if (Size(oneSided) == 2) {
        result = min(result, takeOneOneSided());
        debug("1 1 sided", result);
        result = min(result, takeTwoOneSided());
        debug("2 1 sided", result);
    }

    printf("%d\n", result);
}

int main() {
    int test = 1;
    scanf("%d", &test);

    FORE (i, 1, test) rob(i);

    return 0;
}