#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define pb push_back
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;

constexpr int INF = 1e9;

int main() {
	cin.tie(0)->sync_with_stdio(0);
	int n, t, k;
    cin >> n >> t >> k;
	assert(1 <= k && k <= t && t <= 1e9);
	vector<int> s(n), e(n);
	vector<int> coords{0, t};
	for(int i = 0; i < n; i++) {
		cin >> s[i] >> e[i];
		coords.pb(s[i]);
		coords.pb(e[i]);
	}
	sort(all(coords));
	coords.erase(unique(all(coords)), coords.end());
	auto comp = [&](int v) {
		return (int)(lower_bound(all(coords), v) - coords.begin());
	};
	vector<int> transitions(sz(coords), INF);
	for(int i = 0; i < n; i++) {
		int S = comp(s[i]);
		int E = comp(e[i]);
		assert(S < E);
		transitions[S] = min(transitions[S], E);
	}
	vector<vector<int>> dp(sz(coords), vector<int>(n+1, -INF));
	dp[0][0] = 0;
	for(int i = 0; i < sz(coords)-1; i++) {
		for(int taken = 0; taken <= n; taken++) {
			if(dp[i][taken] == -INF)
				continue;
			if(taken < n && transitions[i] != INF) {
				int next = transitions[i];
				dp[next][taken+1] = max(dp[next][taken+1], dp[i][taken]);
			}
			dp[i+1][taken] = max(dp[i+1][taken], dp[i][taken]+coords[i+1]-coords[i]);
		}
	}

	int ans = 0;
	for(int take = 0; take <= n; take++) {
		if(dp[sz(coords)-1][take] >= k)
			ans = take;
	}
	cout << ans << "\n";
}