#include <iostream>
#include <iomanip>
using namespace std;
int main(){
    int n,m;
    double t;
    cin >> n;
    for(int i=0;i<n;i++){
        t = 0;
        cin >> m;
        if(m==1){
            cout << "1.00" << endl;
            continue;
        }
        for(int j =m/2+1;j<=m-m%2;j++)
            t += 1.0/j;
        t += m%2==0?0:1.0/m;
        cout << setiosflags(ios::fixed) << setprecision(2) << t << endl;
    }
}