#include<stdio.h>

long long v[1000002];

int main()
{
    freopen("gardieni.in","r",stdin);
    freopen("gardieni.out","w",stdout);
    int n,t,a,b,c,i,j;
    long long s=0;
    scanf("%d%d",&n,&t);
    for(i=1;i<=n;++i)
    {
        scanf("%d%d%d",&a,&b,&c);
        for(j=a;j<=b;++j)
            if(v[j]==0||v[j]>c)
                v[j]=c;
    }
    for(i=1;i<=t;++i)
        s+=v[i];
    printf("%lld\n",s);
    return 0;
}