#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <sstream>
#include <complex>
#include <ctime>
#include <cassert>
#include <functional>

using namespace std;

typedef long long ll;
typedef vector<int> VI;
typedef pair<int,int> PII;

#define REP(i,s,t) for(int i=(s);i<(t);i++)
#define FILL(x,v) memset(x,v,sizeof(x))
#define MAXN 5005

const ll INF = (int)1e18;
ll dp[2*MAXN][MAXN];
int main() {
  int n, t, k;
  cin >> n >> t >> k;
  vector<PII> meets;
  VI vs;
  REP(i,0,n) {
    int s, e;
    cin >> s >> e;
    meets.push_back({e, s});
    vs.push_back(s);
    vs.push_back(e);
  }
  vs.push_back(0);
  sort(vs.begin(), vs.end());
  vs.erase(unique(vs.begin(), vs.end()), vs.end());
  int vsz = (int)vs.size();
  sort(meets.begin(), meets.end());

  REP(i,0,vsz) REP(j,0,n+1) dp[i][j] = INF;
  dp[0][0] = 0;
  int pe = 0;
  REP(i,0,n) {
    int e = lower_bound(vs.begin(), vs.end(), meets[i].first) - vs.begin();
    if (e > pe) {
      REP(ce,pe+1,e+1) REP(j,0,n+1) dp[ce][j] = min(dp[ce][j], dp[ce-1][j]);
      pe = e;
    }
    int s = lower_bound(vs.begin(), vs.end(), meets[i].second) - vs.begin();
    int len = meets[i].first - meets[i].second;
    REP(j,0,i+1) {
      if (dp[s][j] != INF) dp[e][j+1] = min(dp[e][j+1], dp[s][j] + len);
    }
  }
  for (int i = n; i >= 0; i--) {
    if (t - dp[vsz - 1][i] >= k) {
      cout << i << endl;
      break;
    }
  }
  return 0;
}