//四則演算 #pragma GCC target("avx") //並列計算 #pragma GCC optimize("O3") //条件分岐を減らす #pragma GCC optimize("unroll-loops") //浮動小数点演算 #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native") #include using namespace std; using ll = long long; using ld = long double; using VI = vector; using VL = vector; using VS = vector; template using PQ = priority_queue, greater>; #define FOR(i,a,n) for(int i=(a);i<(n);++i) #define eFOR(i,a,n) for(int i=(a);i<=(n);++i) #define rFOR(i,a,n) for(int i=(n)-1;i>=(a);--i) #define erFOR(i,a,n) for(int i=(n);i>=(a);--i) #define each(i, a) for(auto &i : a) #define SORT(a) sort(a.begin(),a.end()) #define rSORT(a) sort(a.rbegin(),a.rend()) #define fSORT(a,f) sort(a.begin(),a.end(),f) #define all(a) a.begin(),a.end() #define out(y,x) ((y)<0||h<=(y)||(x)<0||w<=(x)) #define tp(a,i) get(a) #define line cout << "-----------------------------\n" #define ENDL(i,n) ((i) == (n) - 1 ? "\n" : " ") #define stop system("pause") constexpr ll INF = 1000000000; constexpr ll LLINF = 1LL << 60; constexpr ll mod = 1000000007; constexpr ll MOD = 998244353; constexpr ld eps = 1e-10; constexpr ld pi = 3.1415926535897932; templateinline bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; }return false; } templateinline bool chmin(T& a, const T& b) { if (a > b) { a = b; return true; }return false; } inline void init() { cin.tie(nullptr); cout.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); } templateinline istream& operator>>(istream& is, vector& v) { for (auto& a : v)is >> a; return is; } templateinline istream& operator>>(istream& is, deque& v) { for (auto& a : v)is >> a; return is; } templateinline istream& operator>>(istream& is, pair& p) { is >> p.first >> p.second; return is; } templateinline vector vec(size_t a) { return vector(a); } templateinline vector defvec(T def, size_t a) { return vector(a, def); } templateinline auto vec(size_t a, Ts... ts) { return vector(ts...))>(a, vec(ts...)); } templateinline auto defvec(T def, size_t a, Ts... ts) { return vector(def, ts...))>(a, defvec(def, ts...)); } templateinline void print(const T& a) { cout << a << "\n"; } templateinline void print(const T& a, const Ts&... ts) { cout << a << " "; print(ts...); } templateinline void print(const vector& v) { for (int i = 0; i < v.size(); ++i)cout << v[i] << (i == v.size() - 1 ? "\n" : " "); } templateinline void print(const vector>& v) { for (auto& a : v)print(a); } inline string reversed(const string& s) { string t = s; reverse(all(t)); return t; } int main() { init(); int n, m; ll a; cin >> n >> m >> a; vector> lrp; lrp.reserve(m); FOR(i, 0, m) { int l, r; ll p; cin >> l >> r >> p; lrp.emplace_back(l - 1, r, p); } SORT(lrp); int idx = 0; auto dp = defvec(-LLINF, n + 1, 2); dp[0][1] = 0; FOR(i, 0, n) { for (; idx < m && tp(lrp[idx], 0) < i; ++idx); for (; idx < m && tp(lrp[idx], 0) == i; ++idx) { auto [l, r, p] = lrp[idx]; chmax(dp[r][1], dp[l][1] + p - (r == n ? 0 : a)); } FOR(j, 0, 2) { chmax(dp[i + 1][0], dp[i][j]); chmax(dp[i + 1][1], dp[i][j] - (i + 1 == n ? 0 : a)); } } print(max(dp[n][0], dp[n][1])); return 0; }