#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using ull=unsigned long long;
using vb=vector<bool>;
using vvb=vector<vb>;
using vd=vector<double>;
using vvd=vector<vd>;
using vi=vector<int>;
using vvi=vector<vi>;
using vl=vector<ll>;
using vvl=vector<vl>;
using pll=pair<ll,ll>;
using tll=tuple<ll,ll>;
using tlll=tuple<ll,ll,ll>;
using vs=vector<string>;
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define rep(i,n) range(i,0,n)
#define rrep(i,n) for(ll i=((ll)n)-1;i>=0;i--)
#define range(i,a,n) for(ll i=((ll)a);i<((ll)n);i++)
#define LINF ((ll)1ll<<60)
#define INF ((int)1<<30)
#define EPS (1e-9)
#define MOD (1000000007ll)
#define fcout(a) cout<<setprecision(a)<<fixed
#define fs first
#define sc second
#define PI (3.1415926535897932384)

int dx[]={1,0,-1,0,1,-1,-1,1},dy[]={0,1,0,-1,1,1,-1,-1};
template<class T>bool chmax(T&a,T b){if(a<b){a=b; return true;}return false;}
template<class T>bool chmin(T&a,T b){if(a>b){a=b; return true;}return false;}
template<class S>S sum(vector<S>&a){return accumulate(all(a),S());}
template<class S>S max(vector<S>&a){return *max_element(all(a));}
template<class S>S min(vector<S>&a){return *min_element(all(a));}
ll max(int a,ll b){return max((ll)a,b);} ll max(ll a,int b){return max(a,(ll)b);}
int sgn(const double&r){return (r>EPS)-(r<-EPS);} // a>0  : sgn(a)>0
int sgn(const double&a,const double&b){return sgn(a-b);} // b<=c : sgn(b,c)<=0

template<class T>void puta(T&&t){cout<<t<<"\n";}
template<class H,class...T>void puta(H&&h,T&&...t){cout<<h<<' ';puta(t...);}
template<class S,class T>void tf(bool b,S t,T f){if(b)puta(t);else puta(f);}
void YN(bool b){tf(b,"YES","NO");}
void Yn(bool b){tf(b,"Yes","No");}
void yn(bool b){tf(b,"yes","no");}
template<class S,class T>ostream&operator<<(ostream&os,pair<S,T>p){os<<"["<<p.first<<", "<<p.second<<"]";return os;};
template<class S>auto&operator<<(ostream&os,vector<S>t){bool a=1;for(auto s:t){os<<(a?"":" ")<<s;a=0;}return os;}
template<class S,class T>auto&operator<<(ostream&os,map<S,T>mp){bool a=1;for(auto p:mp){os<<(a?"":", ")<<p;a=0;}return os;}
template<class S>auto&operator>>(istream&is,vector<S>&t){for(S&a:t)cin>>a;return is;}

/*他のライブラリを入れる場所*/
map<int,int> zip;
int unzip[500000];

int compress(vector<int> &x) {
    sort(x.begin(), x.end());
    x.erase(unique(x.begin(),x.end()),x.end());
    for(int i = 0; i < x.size(); i++){
        zip[x[i]] = i;
        unzip[i] = x[i];
    }
    return x.size();
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll n,c;
    cin>>n>>c;
    vl a(n),b(n),v(n);
    vi tmp;
    rep(i,n){
        cin>>a[i]>>b[i]>>v[i];
        tmp.push_back(a[i]);
        tmp.push_back(b[i]+1);
    }
    compress(tmp);

    vl imos(n*2+1, 0);
    rep(i,n){
        imos[zip[a[i]]]+=v[i];
        imos[zip[b[i]+1]]-=v[i];
    }
    partial_sum(all(imos), imos.begin());

    ll ans=0;
    rep(i,n*2+1){
        ll d=unzip[i+1]-unzip[i];
        if(d<=0)continue;
        ans+=min(c, imos[i]) * d;;
    }
    puta(ans);
    return 0;
}
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef	long long ll;
typedef long double ld;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef set<int> si;
typedef map<int,int> mii;
typedef map<ll,ll> mll;
typedef vector<pii> vii;
typedef vector<pll> vll;
#define fi first
#define se second
#define pi 3.141592653589793
#define mod 998244353
#define pb push_back
#define mp make_pair
#define all(v) v.begin(),v.end()
#define pqmax priority_queue<int>
#define pqmin priority_queue<int,vi,greater<int>>
#define fio ios_base::sync_with_stdio(0), cin.tie(NULL)
#define tc int tt;cin>>tt;for(int ti=1;ti<=tt;ti++)
#define case_g "Case #"<<ti<<": "
#define RED "\033[31m"
#define GREEN "\033[32m"
#define RESET "\033[0m"
#define sleep for (int i = 1, a;i < 100000000;i++, a = a * a)
typedef tree<pii, null_type, less<pii>, rb_tree_tag, tree_order_statistics_node_update> ranked_pairset;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ranked_set;
typedef tree<int, int, less<int>, rb_tree_tag, tree_order_statistics_node_update> ranked_map;

int main() {
	fio;
	ll n, p;
	cin >> n >> p;
	mll m;
	for (int i = 0;i < n;i++) {
		int a, b, c;
		cin >> a >> b >> c;
		m[a] += c;
		m[b + 1] -= c;
	}
	ll cur = 0, ans = 0;
	for (auto itr = m.begin();next(itr) != m.end();itr++) {
		ll d = next(itr)->fi - itr->fi;
		cur += itr->se;
		ll c = min(cur, p);
		ans += d * c;
	}
	cout << ans << '\n';
}
