1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 using namespace std;
 5 const int N=1010;
 6 int n,m,r,f[N];
 7 struct fx{
 8     int st,ed,v;
 9 }c[N];
10 bool cmp(fx a,fx b){
11     return a.ed<b.ed;
12 }
13 int read(){
14     int sum=0;
15     char ch=getchar();
16     while (ch<‘0‘||ch>‘9‘)
17         ch=getchar();
18     while (ch>=‘0‘&&ch<=‘9‘){
19         sum=sum*10+ch-‘0‘;
20         ch=getchar();
21     }
22     return sum;
23 }
24 int main(){
25     int st,ed,v,ans=0;
26     n=read();
27     m=read();
28     r=read();
29     for (int i=1;i<=m;i++){
30         c[i].st=read();
31         c[i].ed=read()+r;
32         c[i].v=read();
33     }
34     sort(c+1,c+m+1,cmp);
35     for (int i=1;i<=m;i++){
36            f[i]=c[i].v;
37         for (int j=1;j<i;j++){
38             if (c[i].st>=c[j].ed)
39                 f[i]=max(f[i],f[j]+c[i].v);
40             ans=max(ans,f[i]);
41         }
42     }
43     printf("%d",ans);
44     return 0;
45 }