#include "bits/stdc++.h"
#include<sstream>
using namespace std;
typedef long long ll;
#define _USE_MATH_DEFINES
#include <math.h>
#define NIL = -1;
#define all(x) x.begin(),x.end()
const ll INF = 1e9;
const long long inf = 1e18;
const ll INFL = 1e18;
const ll MOD = 1e9 + 7;
 
int digit(ll x) {
    int digits = 0;
 
    while(x > 0){
        x /= 10;
        digits++;
    }
 
    return digits;
}
 
ll gcd(long long a,long long b) {
    if (a < b) swap(a,b);
    if (b == 0) return a;
    
    return gcd(b,a%b);
}
 
bool is_prime(long long N){
    if (N == 1) return false;
    for (long long i = 2;i * i <= N;i++){
        if (N % i == 0) return false;
    }
    return true;
}
 
ll lcm(ll a,ll b){
    return ((a * b == 0)) ? 0 : (a / gcd(a,b) * b);
}
 
double DegreeToRadian(double degree){
    return degree * M_PI / 180.0;
}
 
long long modpow(long long a, long long b, long long m){
    long long ans = 1;
    while(b > 0){
        if (b % 2 == 1){
            ans *= a;
            ans %= m;
        }
        a *= a;
        a %= m;
        b /= 2;
    }
    return ans;
}

long long comb(long long x, long long y){
    int z;
    if (y == 0) return 1;
    else {
        z = modpow(x, y/2, MOD)*modpow(x, y/2, MOD)%MOD;
        if (y % 2 == 1) z = z*x%MOD;
        return z;
    }
}


vector<pair<long long, long long>> prime_fact(long long x){
    vector<pair<long long, long long>> res;
    for(int i = 2;i*i <= x;i++){
        if (x % i == 0){
            long long cnt = 0;
            while(x % i == 0){
                cnt++;
                x /= i;
            }
            res.push_back({i, cnt});
        }
    }
    if (x != 1){
        res.push_back({x, 1});
    }
    return res;
}

int64_t mod_inv(int64_t a, int64_t m){
    int64_t b = m, u = 1, v = 0;

    while(b){
        int64_t t = a/b;
        a -= t*b;
        swap(a, b);
        u -= t*v;
        swap(u, v);
    }
    u %= m;
    if (u < 0) u += m;

    return u;
}


// {g, x, y}: ax + by = g
tuple<long long, long long, long long> extgcd(long long a, long long b){
    if (b == 0) return {a, 1, 0};
    long long g, x, y;
    tie(g, x, y) = extgcd(b, a % b);
    return {g, y, x - a/b*y};
}

int dx[4] = {0,1,0,-1};
int dy[4] = {1,0,-1,0};

 
///////////////////////////////////////////////////////////////

int main(){
    long long N, C;
    cin >> N >> C;
    vector<pair<long long, long long>> p;
    for(int i = 0;i < N;i++){
        long long a, b, c;
        cin >> a >> b >> c;
        p.push_back({a - 1, c});
        p.push_back({b, -c});
    }
    sort(p.begin(), p.end());
    long long ans = 0, cost = 0, t = 0;
    for(auto [x, y] : p){
        if (t != x){
            ans += min(C, cost)*(x - t);
            t = x;
        }
        cost += y;
    }

    cout << ans << endl;

}
#include <bits/stdc++.h>
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define ll long long
#define ALL(a) (a).begin(),(a).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define rrep(i,n) for(int i=n-1;i>=0;i--)
#define fi first
#define se second
#define pb push_back
#define Pii pair<int,int>
#define Pll pair<long long,long long>
#define fout(num) cout << fixed << setprecision(20) << (num) << endl
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}
//vector<vector<ll>> dp(n,vector<ll>(n))
//2-dim:vector<vector<Type>> vv(n, vector<Type>(m, d));
//3-dim:vector<vector<vector<Type>>> vvv(n, vector<vector<Type>>(m, vector<Type>(l, d)));

using namespace std;

signed main(){
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    int n; cin >> n;
    ll x; cin >> x;
    map<ll,ll> mp;
    vector<Pll> v;
    rep(i,n){
        int a,b; cin >> a >> b;
        ll c; cin >> c;
        mp[a]+=c;
        mp[b+1]-=c;
        v.pb({a,c});
        v.pb({b+1,-c});
    }
    sort(ALL(v));
    ll now = 1;
    ll ans = 0;
    ll kane = 0;
    for(auto itr=mp.begin();itr!=mp.end();itr++){
        ll d = itr->fi;
        ans += (d-now)*min(x,kane);

        kane += itr->se;
        now = d;
    }
    cout << ans << endl;
    return 0;
}
// g++ main.cpp -o a.out && ./a.out