#include<iostream>
#include<string>
#include<iomanip>
#include<cmath>
#include<vector>
#include<algorithm>

using namespace std;

#define int long long
#define rep(i,n) for(int i = 0; i < (n); i++)
#define INF ((long long)1e18)
#define MOD ((int)1e9+7)
#define endl "\n"

#define yn(f) ((f)?"Yes":"No")
#define YN(f) ((f)?"YES":"NO")

#define MAX

signed main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(10);
	
	int N, K, A, B;
	vector<pair<int,int>> hoge;
	
	cin>>N>>K;
	
	for(int i = 0; i < N; i++){
		cin>>A>>B;
		hoge.push_back(make_pair(A,0));
		hoge.push_back(make_pair(B+1,1));
	}
	
	sort(hoge.begin(), hoge.end());
	
	for(int i = 0, j = 0, num = 0, mai = 0; j <= (int)(1e9);){
		while(i != hoge.size() && hoge[i].first == j){
			if(hoge[i].second){
				num--;
			} else {
				num++;
			}
			i++;
		}
		mai += num;
		// cout<<hoge[i].first<< " "<< num<<" "<<mai<<endl;
		if(mai >= K){
			cout<<j<<endl;
			return 0;
		}
		j++;
	}
	return 0;
}