A

#include <bits/stdc++.h>

using namespace std;

int main() {
    int t;
    cin>>t;

    while(t--){
        int n;
        string s;
        cin>>n>>s;

        int ans = 0;

        for(int i=0; i<n; i++)
        {
            if(i<n-1 && s[i]=='*' && s[i+1]=='*')     break;

            ans += (s[i] == '@');
        }

        cout<<ans<<"\n";
    }
}