#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
#define endl '\n'
//#pragma GCC optimize("Ofast")
using namespace std;
using ll = long long;
using ld = long double;
using pii = pair < int, int >;
using pll = pair < ll, ll >;
const ll INF = 2e18;
const ll DIM = 100007;
const ll DIMQ = 2007;
const ld PI = 3.1415926535;
const int mod = 998244353;
struct interval {
int l, r, c;
};
bool cmp(interval i1, interval i2) {
if(i1.l != i2.l) return i1.l < i2.l;
return i1.r < i2.r;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#ifdef IloveCP
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
int n, m, k;
cin >> n >> m >> k;
vector < interval > a(m + 1);
for(int i = 1; i <= m; i++) {
cin >> a[i].l >> a[i].r >> a[i].c;
}
sort(a.begin(), a.end(), cmp);
vector < vector < ll > > dp(m + 2, vector < ll >(k + 1, INF));
dp[0][0] = 0;
for(int i = 0; i <= m; i++) {
vector < pii > to;
for(int j = 1; j <= m; j++) {
if(a[j].l >= a[i].r) to.push_back({a[j].r, j});
}
sort(to.begin(), to.end());
for(int x = 0; x <= k; x++) {
if(dp[i][x] >= INF) continue;
ll cost = 0;
for(int j = 0; j < to.size(); j++) {
if(x != k) dp[to[j].second][x + 1] = min(dp[to[j].second][x + 1], dp[i][x] + cost);
cost += a[to[j].second].c;
}
dp[m + 1][x] = min(dp[m + 1][x], dp[i][x] + cost);
}
}
ll res = m;
for(int i = 0; i <= k; i++) res = min(res, dp[m + 1][i]);
cout << res << endl;
return 0;
}
