#include<bits/stdc++.h>
#define LL long long
#define pb push_back
#define SZ(x) ((int)x.size()-1)
#define ms(a,b) memset(a,b,sizeof a)
#define F(i,a,b) for (int i=(a);i<=(b);++i)
#define DF(i,a,b) for (int i=(a);i>=(b);--i)
//#define mp make_pair
//#define OO(x) fixed<<setprecision(x)
using namespace std;
//mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
inline int read(){
	char ch=getchar(); int w=1,c=0;
	for(;!isdigit(ch);ch=getchar()) if (ch=='-') w=-1;
	for(;isdigit(ch);ch=getchar()) c=(c<<1)+(c<<3)+(ch^48);
	return w*c;
}
const int M=5050;
int n,k,a[M],num[M][M],ct;
LL dp[M],val[M],L[M],R[M],t[M];
vector<int> v[M]; 
int main(){
//	freopen(".in","r",stdin);
//	freopen(".out","w",stdout);
	n=read(); k=read();
	F(i,1,n){
		L[i]=read(); R[i]=read(); t[++ct]=L[i]; t[++ct]=R[i]; a[i]=read();
	}
	sort(t+1,t+ct+1);
	int N=unique(t+1,t+ct+1)-t-1;
	F(i,1,n){
		L[i]=lower_bound(t+1,t+N+1,L[i])-t;
		R[i]=lower_bound(t+1,t+N+1,R[i])-t;
		F(j,L[i],R[i]-1) val[j]+=a[i];
		v[L[i]].pb(i);
//		cerr<<L[i]<<" "<<R[i]<<"   interval\n";
	}
	dp[0]=0;
	F(i,1,N){
		dp[i]=1e18;
		priority_queue<int> q;
		LL co=0;
		DF(j,i-1,0){
			for (int id:v[j+1]) if (R[id]<=i){
				q.push(-a[id]);
				while (q.size()>k) co-=q.top(),q.pop(); 
			}
//			cerr<<i<<" -> "<<j<<" "<<co<<"   jjjj\n";
			dp[i]=min(dp[i],dp[j]+val[i]+co);//,cerr<<j<<" "<<i<<" "<<num[j+1][i]<<"   oooooo\n";
		}	
//		cerr<<val[i]<<" "<<dp[i]<<"\n";
	}
	cout<<dp[N]<<"\n";
	return 0;
}
/* stuff you should look for
	* int overflow, array bounds
	* special cases (n=1?)
	* do smth instead of nothing and stay organized
	* WRITE STUFF DOWN
	* DON'T GET STUCK ON ONE APPROACH
*/