#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>

#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <algorithm>
using namespace std;

struct ev
{
    int tipo; //1=sobe 2=desce
    long long h, x;

    bool operator<(const ev& e) const
    {
        if(x != e.x) return x<e.x;

        if(tipo == 1 && e.tipo == 1) return h < e.h;
        if(tipo == 2 && e.tipo == 2) return h > e.h;

        return (tipo == 2);
    }

    ev(int tipo, long long x, long long h): x(x), h(h), tipo(tipo) {}
    ev(){}
};


#define MAX 80400

ev evs[MAX];

multiset<long long, greater<long long> > heap;

int main(void)
{
    int n, i, j;
    long long res;
    long long a, b, h;

    scanf("%d", &n);
    for(i=0; i<n; i++)
    {
        scanf("%lld %lld %lld", &a, &b, &h);

        evs[2*i] = ev(1, a, h);
        evs[2*i+1] = ev(2, b, h);
    }

    sort(evs, evs + 2*n);

    res = 0;
    long long ultx = 0, ulth = 0;
    //for(set<ev>::iterator it = evs.begin(); it != evs.end(); ++it)
    for(ev* it = evs; it != (evs+2*n); it++)
    {
        if(it->tipo == 1)
        {
            res += (it->x - ultx) * (ulth);
            heap.insert(it->h);

            //printf("sobe x=%d h=%d res=%d\n", it->x, it->h, res);
        }
        else
        {
            res += (it->x - ultx) * (ulth);
            heap.erase(heap.find(it->h));

            //printf("desce x=%d h=%d res=%d\n", it->x, it->h, res);
        }

        ultx = it->x;
        ulth = *heap.begin();
    }

    printf("%Ld\n", res);

    return 0;
}