#include <bits/stdc++.h>
#define LL long long
using namespace std;
struct Event{
	int x,val;
	bool operator<(Event e){
		return x<e.x;
	}
}event[1000000];
struct Line{
	LL k,b;
	LL operator()(int x){
		return 1ll*k*x+b;
	}
}tree[1000000];
int ls[1000000],rs[1000000],tot=1;
void change(int p,int l,int r,Line line){
	if(tree[p](l)>=line(l)&&tree[p](r)>=line(r)) return;
	if(tree[p](l)<=line(l)&&tree[p](r)<=line(r)){
		tree[p]=line;
		return;
	}
	int mid=(l+r)>>1;
	if(ls[p]==0){
		ls[p]=++tot;
		tree[tot].b=-1000000000000ll;
	}
	change(ls[p],l,mid,line);
	if(rs[p]==0){
		rs[p]=++tot;
		tree[tot].b=-1000000000000ll;
	}
	change(rs[p],mid+1,r,line);
}
LL query(int p,int l,int r,int pos){
	if(p==0) return -1000000000000ll;
	int mid=(l+r)>>1;
	LL val=tree[p](pos);
	if(pos<=mid) return max(query(ls[p],l,mid,pos),val);
	else return max(query(rs[p],mid+1,r,pos),val);
}
Line li[1000000];
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	tree[1].b=-1000000000000ll;
	int n;
	cin>>n;
	LL shift=0;
	for(int i=1;i<=n;i++){
		int a,b,x;
		cin>>a>>b>>x;
		shift-=x*4ll;
		x*=2;
		event[i*2-1]={a,x};
		event[i*2]={b,x};
	}
	sort(event+1,event+n*2+1);
	LL sum=0,ans=0;
	for(int i=1;i<=n*2;i++){
		sum+=event[i].val;
		li[i]={-4ll*event[i].x,sum};
		//change(1,1,1000000000,{-4ll*event[i].x,sum});
	}
	sum=0;
	for(int i=1;i<=n*2;i++){
		sum+=event[i].val;
		for(int j=1;j<=n*2;j++) ans=max(ans,sum+li[j](event[i].x));
		//ans=max(ans,sum+query(1,1,1000000000,event[i].x));
	}
	ans+=shift;
	if(ans<0){
		cout<<'-';
		ans=-ans;
	}
	cout<<(ans>>2)<<'.';
	if((ans&3)==0) cout<<"00\n";
	if((ans&3)==1) cout<<"25\n";
	if((ans&3)==2) cout<<"50\n";
	if((ans&3)==3) cout<<"75\n";
	return 0;
}