bool M1;
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#include<climits>
#include<iomanip>
#include<cassert>
#include<random>
#include<cstdio>
#include<vector>
#include<bitset>
#include<stack>
#include<queue>
#include<deque>
#include<cmath>
#include<ctime>
#include<map>
#include<set>
//#include<ext/pb_ds/assoc_container.hpp>
//#include<ext/pb_ds/hash_policy.hpp>
//#include<ext/pb_ds/priority_queue.hpp>
#define fi first
#define se second
#define ll long long
#define Vector Point
#define I128 __int128
#define LD long double
#define ull unsigned ll
#define pii pair<int,int>
#define pb(x) push_back(x)
#define syt cerr<<"sytakioi\n"
#define F(i,a,b) for(int i=a,i##end=b;i<=i##end;++i)
#define UF(i,a,b) for(int i=a,i##end=b;i>=i##end;--i)
#define look_memory cerr<<abs(&M2-&M1)/1024.0/1024<<'\n'
#define rd_i(l,r) uniform_int_distribution<int>(l,r)(rd)
#define rd_r(l,r) uniform_real_distribution<double>(l,r)(rd)
#define look_time cerr<<(clock()-Time)*1.0/CLOCKS_PER_SEC<<'\n'
using namespace std;
//using namespace __gnu_cxx;
mt19937 rd(time(0));
const int N=1e5+5;
int n;
int c[N],fa[N];
LD p[N],ans;
vector<int> e[N];
struct node{
	LD c,p;int id;
	node(LD _c,LD _p,int _i):c(_c),p(_p),id(_i){}
	bool operator < (const node &x)const{return c+p*x.c==x.c+x.p*c?x.id<id:c+p*x.c>x.c+x.p*c;}
	bool operator == (const node &x)const{return c==x.c&&p==x.p&&id==x.id;}
};
int id[N];
priority_queue<node> q[N];
inline void merge(int &x,int &y){
	if(q[x].size()<q[y].size()) swap(x,y);
	while(!q[y].empty()) q[x].emplace(q[y].top()),q[y].pop();
}
inline void dfs(int u){
	id[u]=u;
	for(int v:e[u]) dfs(v),merge(id[u],id[v]);
	if(u){
		LD C=0,P=1;
		while(!q[id[u]].empty()&&node(c[u]+p[u]*C,p[u]*P,u)<q[id[u]].top()){
			node x=q[id[u]].top();q[id[u]].pop();
			C+=P*x.c;P*=x.p;
		}
		q[id[u]].emplace(c[u]+p[u]*C,p[u]*P,u);
	}
}
bool M2;
int main(){
	int Time=clock();
	look_memory;
//	freopen("data20.in","r",stdin);
//	freopen("1.out","w",stdout);
	cin.tie(nullptr)->sync_with_stdio(false);
	cin>>n;
	F(i,1,n) cin>>c[i]>>p[i]>>fa[i],e[fa[i]].emplace_back(i);
	dfs(0);
	LD C=0,P=1;
	while(!q[id[0]].empty()){
		node x=q[id[0]].top();q[id[0]].pop();
//		cout<<x.c<<' '<<x.p<<' '<<x.id<<'\n';
		C+=P*x.c;P*=x.p;
	}
	cout<<fixed<<setprecision(9)<<C<<'\n';
	look_time;
	return 0;
}