30pt WA一个点求调:(

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
char buf_ans[114];
ll next_n(double last_ans=0,ll get_n=0){
	//last_ans<n<=1e18
	sprintf(buf_ans,"%.6f",last_ans);
	for(ll i=0,x=0;;i++){
		if(buf_ans[i]=='.')return get_n^x;
		if(i&1)x*=10;
		else x=x*10+(buf_ans[i]^48);
	}
}
double lans;
int T;
ll n;
ll f[6000005];
ll calc(double x){
    ll re=floor(sqrt(sqrt(x))+0.5);
    return re;
}
const int N=31623;
double pre[6000060];
void Init(){
    auto x=[](ll i){
        long long l=0,r=1e18,ans=0;
        while(l<=r){
            ll mid=(l+r)>>1;
            if(calc(mid)>i)r=mid-1;
            else ans=mid,l=mid+1;
        }
        return ans;
    };
    for(int i=1;i<=N;++i){
        f[i]=x(i);
        pre[i]=pre[i-1]+1.0*(f[i]-f[i-1])*(1/(1.0*i));
    }
}

int main(){
    scanf("%d",&T);
    Init();
    while(T--){
        scanf("%lld",&n); n=next_n(lans,n);
        int p=lower_bound(f+1,f+1+N,n)-f;
       if(f[p]==n)lans=pre[p];
       else lans=pre[p-1]+(n-f[p-1])*(1.0/(1.0*p));
        printf("%.6lf\n",lans);
    }
    return 0;
}