#include<bits/stdc++.h>
using namespace std;
int n;
double a[1050000],t,p[1050000],pp[1050000],as,t1,t2;
int main(){
    freopen("get_bag.in","r",stdin);
    freopen("get_bag.out","w",stdout);
    t1=clock();
    ios::sync_with_stdio(false);
    cin>>n,p[0]=1;
    for(int i=0;i<(1<<n);i++) cin>>a[i];
    while(++t){
        t2=clock();
        if(t2-t1>900) break;
        for(int i=0;i<(1<<n);i++) pp[i]=0;
        for(int i=0;i<(1<<n);i++){
            for(int j=0;j<(1<<n);j++){
                pp[i|j]+=pp[i]*a[j];
            }
        }
        for(int i=0;i<(1<<n);i++) p[i]+=pp[i];
        as+=p[(1<<n)-1]*t;
    }
    if(as<1e-6) cout<<"INF";
    else cout<<as;
    return 0;
}