#include <stdio.h>
#define lim 1000005
int v[lim];
int main(){
    FILE *fin,*fout;
    fin=fopen("gardieni.in","r");
    fout=fopen("gardieni.out","w");
    int i,j,a,b,c,n,t;
    long long cost=0;
    fscanf(fin,"%d%d",&n,&t);
    for(i=1;i<=n;i++){
        fscanf(fin,"%d%d%d",&a,&b,&c);
        for(j=a;j<=b;j++)
            if(c<v[j]||v[j]==0)
                v[j]=c;
    }
    for(i=1;i<=t;i++)
        cost=cost+(long long)v[i];
    fprintf(fout,"%lld",cost);
    fclose(fin);
    fclose(fout);
    return 0;
}