#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

void solve(){

int a,b;cin>>a>>b;

string str; cin >> str;

int result = 0;

for (int i = 0; i < a; i++) if (str[i] == '1') result += 11;

for (int i = 0; i <= b; i++) {

int c = a-1-i;

if (c<0)break;

if (str[c] == '1') {

b-=i;

str[c]='0';

str[a-1]='1';

result-=10;

break;

}

}

for (int i = 0; i <= b; i++) {

if (i == a-1) break;

if (str[i] == '1') {

result-=1;

break;

}

}

cout << result;

}

int main()

{

cin.tie(0)->sync_with_stdio(false);

int T = 1;

cin >> T;

while (T--) {

solve();

cout << '\n';

}

return 0;

}