#include<cstdio>#include<string>#include<cstring>#include<iostream>#include<cmath>#include<algorithm>using namespace std;struct eg{int x,y,w;}e[1005];bool cmp(eg a,eg b){if(a.x==b.x)return a.y<b.y;return a.x<b.x;}int main(){int n,m,r,dp[1005],ans;scanf("%d%d%d",&n,&m,&r);for(int i=0;i<m;i++){scanf("%d%d%d",&e[i].x,&e[i].y,&e[i].w);}sort(e,e+m,cmp);ans=0;for(int i=0;i<m;i++)dp[i]=e[i].w;for(int i=0;i<m;i++){for(int j=0;j<i;j++){if(e[i].x>=e[j].y+r)dp[i]=max(dp[i],dp[j]+e[i].w);}ans=max(ans,dp[i]);}printf("%dn",ans);return 0;}
