#include<bits/stdc++.h>
using namespace std;
const int maxn=1<<21;
double dp[maxn];
double p[21];
int main(){
    int n;
    while(scanf("%d",&n)!=EOF){
        for(int i=0;i<n;i++)
            scanf("%lf",&p[i]);
        dp[(1<<n)-1]=0;
        for(int s=(1<<n)-2;s>=0;s--){
            double sum=1.0,sump=0;
            for(int j=0;j<n;j++){
                if(!((1<<j)&s)){
                    sum+=dp[s|(1<<j)]*p[j];
                    sump+=p[j];
                }
            }
            dp[s]=sum/sump;
        }
        cout<<dp[0]<<"++++"<<endl;
        printf("%.5f\n",dp[0]);
    }
    return 0;
}