#include<bits/stdc++.h>
#define Gc() getchar() 
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define PB push_back
#define fi first
#define se second
using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;
using namespace std;const int N=5e5+5,M=1e3+5,K=100+5,mod=1e9+7,Mod=mod-1;const db eps=1e-9;const ll INF=1e18+7;mt19937 rnd(time(0));
int n,m,k,x,y,z,S,T;
struct yyy{int to,w,g,z;};struct ljb{int head=1,h[N];yyy f[N*4];void add(int x,int y,int w,int g){f[++head]=(yyy){y,w,g,h[x]};h[x]=head;}}s;
void con(int x,int y,int w,int g){s.add(x,y,w,g);s.add(y,x,-w,0);}
namespace MCMF{
	ll d[N];int g[N],pre[N];
	priority_queue<pair<int,int> > Q;
	int bfs(){
		Me(d,0x3f);d[S]=0;g[S]=1e9;Q.push({0,S});while(!Q.empty()){
			auto x=Q.top();Q.pop();if(x.fi!=-d[x.se]) continue;
			yyy tmp;for(int i=s.h[x.se];i;i=tmp.z){
				tmp=s.f[i];if(!tmp.g||d[tmp.to]<=d[x.se]+tmp.w) continue;pre[tmp.to]=i;
				d[tmp.to]=d[x.se]+tmp.w;g[tmp.to]=min(g[x.se],tmp.g);Q.push({-d[tmp.to],tmp.to});
			}
		}
		return d[T]<INF;
	}
	ll calc(){
		ll ans=0;while(bfs()){
			ans+=g[T]*d[T];int x=T;while(x^S) s.f[pre[x]].g-=g[T],s.f[pre[x]^1].g+=g[T],x=s.f[pre[x]^1].to;
		}
		return ans;
	}
}
int main(){
	int i,j;scanf("%d%d%d",&n,&m,&k);
	S=0;T=n+1;for(i=0;i<=n;i++) con(i,i+1,0,k);
	for(i=1;i<=m;i++) scanf("%d%d%d",&x,&y,&z),con(x,y+1,-z,1);
	printf("%lld\n",-MCMF::calc());
}