import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }

string COLOR(string s = "") { return "\x1b[" ~ s ~ "m"; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


enum INF = 10L^^18;

void main() {
  try {
    for (; ; ) {
      const N = readInt;
      const S = readLong;
      const H = readLong;
      auto X = new long[N];
      auto Y = new long[N];
      auto Z = new long[N];
      foreach (i; 0 .. N) {
        X[i] = readLong;
        Y[i] = readLong;
        Z[i] = readLong;
      }
      
      auto ZSum = new long[N + 1];
      foreach (i; 0 .. N) {
        ZSum[i + 1] = ZSum[i] + Z[i];
      }
      
      auto fs = new long[N];
      auto gs = new long[N];
      fs[] = -INF;
      gs[] = -INF;
      
      alias Entry = Tuple!(long, "val", int, "j");
      DList!Entry queF;
      auto maxGs = new long[N + 1];
      maxGs[0] = -INF;
      
      int jH, jS;
      foreach (i; 0 .. N) {
        // start: need sleep >= H
        for (; X[i] - Y[jH] >= H; ++jH) {}
        if (0 < jH) {
          // chmax(fs[i], gs[0 .. jH].maxElement);
          chmax(fs[i], maxGs[jH]);
        }
        chmax(fs[i], 0);
        fs[i] -= ZSum[i];
        for (; !queF.empty && queF.back.val <= fs[i]; queF.removeBack) {}
        queF.insertBack(Entry(fs[i], i));
        
        // end: wake up <= S
        for (; jS < i + 1 && Y[i] - X[jS] > S; ++jS) {}
        if (jS < i + 1) {
          // chmax(gs[i], fs[jS .. i + 1].maxElement + ZSum[i + 1]);
          for (; !queF.empty && queF.front.j < jS; queF.removeFront) {}
          if (!queF.empty) {
            chmax(gs[i], queF.front.val + ZSum[i + 1]);
          }
        }
        maxGs[i + 1] = max(maxGs[i], gs[i]);
      }
      debug {
        writeln("fs = ", fs);
        writeln("gs = ", gs);
      }
      long ans = gs.maxElement;
      chmax(ans, 0);
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}