#include<bits/stdc++.h>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<queue>
#include<deque>
#include<list>
#include<set>
#include<map>
#include<vector>
#include<iostream>
#define re register
//#define inf 0x7f7f7f7f
#define inl inline
#define sqr(x) ((x)*(x))
#define ls (x<<1)
#define rs (x<<1|1)
#define mp(a,b) make_pair((a),(b))
#define debug printf("***************\n");
//#define ls (x<<1)
//#define rs (x<<1|1)
// #pragma comment(linker, "/STACK:1024000000,1024000000")
// #pragma GCC optimize (2)
// #pragma G++ optimize (2)
using namespace std;
typedef int ll;
typedef pair<ll,ll> pll;
typedef double dou;
const ll mod=1e9+7;
//const ll base;
const ll MAXN=50+5;
// const ll MAXM;
const dou eps=1e-8;
ll gcd(ll x,ll y) {while(y^=x^=y^=x%=y);return x;}
// inl char gc() {
//     static char buf[1000000],*p1=buf,*p2=buf;
//     return p1==p2&&(p2=(p1=buf)+fread(buf,1,1000000,stdin),p1==p2)?EOF:*p1++;
// }
inl char gc() {
    return getchar();
}
inl ll read() {
    re ll x = 0; re int f = 1;
    re char ch = gc();
    while(ch<'0'||ch>'9') { if(ch== '-' ) f = -1; ch = gc(); }
    while(ch>='0'&&ch<='9') {x=(x<<1)+(x<<3)+(ch^48);ch=gc();}
    return x * f;
}
inl ll readx() {
	re ll x=0; re int f=1;
	re char ch=gc();
	while(ch<'0'||ch>'9') { if(ch== '-' ) f = -1; ch = gc(); }
	return ch^48;
}
inl char readc() {
    re char ch=gc();
    while((ch<'A'||ch>'Z')&&(ch<'a'||ch>'z')) ch=gc();
    return ch;
}
void write(ll x){
    if(x>9)write(x/10);
    putchar(x%10+'0');
}
inl void writel(ll x) {
    if(x<0) {x=-x;putchar('-');}
    write(x); putchar(' ');
}
inl void writeln(ll x){
    if(x<0) {x=-x;putchar('-');}
    write(x); puts("");
}
inl void FR() {
	freopen(".in","r",stdin);
	freopen(".out","w",stdout);
}
inl void FC() {
	fclose(stdin);
	fclose(stdout);
}

double x[MAXN],y[MAXN];
double p[MAXN];
double cj(double x1,double y1,double x2,double y2) {
    return (x1 * y2 - y1 * x2);
}


int main() {
// FR();
    ll n=read();
    for(re ll i=1;i<=n;i++) {
        cin>>x[i]>>y[i]>>p[i];
    }
    double ans=0;
    for(re ll i=1;i<=n;i++) {
        for(re ll j=1;j<=n;j++) {
            if(i!=j) {
                double s=cj(x[i],y[i],x[j],y[j])*p[i]*p[j];
                for(re ll k=1;k<=n;k++) {
                    if(k!=i&&k!=j) {
                        if(cj(x[k]-x[i],y[k]-y[i],x[j]-x[i],y[j]-y[i])<=eps) {//在右侧
                            s=s*(1.0-p[k]);
                        }
                    }
                }
                ans=ans+s;
            }
        }
    }
    cout<<fixed<<setprecision(6)<<abs(ans/2)<<endl;
    int a=1;
//	FC();
	return 0;
}
/*

*/