#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
template <typename T> inline void read(T &F) {
    int R = 1; F = 0; char CH = getchar();
    for(; !isdigit(CH); CH = getchar()) if(CH == '-') R = -1;
    for(; isdigit(CH); CH = getchar()) F = F * 10 + CH - 48;
    F *= R;
}
inline void file(string str) {
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
}
const int N = 1e5 + 10;
char s[N]; int n;
int main() {
    //file("");
    int T; read(T);
    while(T--) {
        read(n); scanf("%s", s + 1);
        int ans = 0;
        for(int i = 1; i <= n; i++) {
            int cnt = 0, x = i - 1;
            if(!(i & 1)) {
                if(s[x] == '1') cnt++;
                for(int j = 1; j < (i & -i); j <<= 1) {
                    x -= j; if(s[x] == '1') cnt++;
                }
            }
            if(cnt == 0 && s[i] == '1') ans++;
            else if(cnt == 1 && s[i] == '0') ans++;
        }
        cout << ans << '\n';
    }   
    
    #ifdef _MagicDuck
        fprintf(stderr, "# Time: %.3lf s", (double)clock() / CLOCKS_PER_SEC);
    #endif
    return 0;
}