#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define INF 1000000000000000000
int main(){
ll n, m, k, l, r, c;
cin>>n>>m>>k;
vector<vector<ll>> ra;
for (int i = 1; i <= m; i++){
cin>>l>>r>>c;
ra.push_back({r, l, c, i});
}
ra.push_back({0, -1, 0, 0});
m++;
sort(ra.begin(), ra.end());
vector<vector<int>> v(m + 1);
for (int i = 0; i < m; i++){
for (int j = i + 1; j < m; j++){
if (ra[i][0] <= ra[j][1]) v[ra[i][3]].push_back(j);
}
}
vector<vector<ll>> dp(m + 1, vector<ll>(k + 1, INF));
dp[0][0] = 0;
for (int i = 0; i < k; i++){
for (auto el : ra){
int ind = el[3];
ll co = 0;
for (auto val : v[ind]){
dp[ra[val][3]][i + 1] = min(dp[ra[val][3]][i + 1], dp[ind][i] + co);
co += ra[val][2];
}
}
}
ll ans = INF;
for (int i = 0; i < m; i++){
ll co = 0;
for (auto val : v[i]){
co += ra[val][2];
}
for (int j = 0; j <= k; j++){
ans = min(ans, dp[i][j] + co);
}
}
cout<<ans;
}
