#include #include using namespace std; using namespace atcoder; //using mint = modint1000000007; //const int mod = 1000000007; //using mint = modint998244353; //const int mod = 998244353; //const int INF = 1e9; const long long LINF = 1e18; #define rep(i, n) for (int i = 0; i < (n); ++i) #define rep2(i,l,r)for(int i=(l);i<(r);++i) #define rrep(i, n) for (int i = (n-1); i >= 0; --i) #define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i) #define all(x) (x).begin(),(x).end() #define allR(x) (x).rbegin(),(x).rend() #define endl "\n" #define P pair template inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; } long long op(long long a, long long b) { return max(a, b); } long long e() { return -LINF; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n, m, a; cin >> n >> m >> a; segtreeseg(n + 1);//最後に引いた所 seg.set(0, 0); rep2(i, 1, n)seg.set(i, -a); vector>v(n); rep(i, m) { int l, r, p; cin >> l >> r >> p; l--, r--; v[l].push_back({ r,p }); } rep(i, n) { { long long val = seg.prod(0, i); rep(j, v[i].size()) { long long nval = val - a * 2 + v[i][j].second; if (v[i][j].first == n - 1)nval += a; long long get = seg.get(v[i][j].first + 1); if (nval > get)seg.set(v[i][j].first + 1, nval); } } { long long val = seg.get(i); rep(j, v[i].size()) { long long nval = val - a + v[i][j].second; if (v[i][j].first == n - 1)nval += a; long long get = seg.get(v[i][j].first + 1); if (nval > get)seg.set(v[i][j].first + 1, nval); } } } long long ans = seg.all_prod(); cout << ans << endl; return 0; }