#include <iostream>
#include <vector>
using namespace std;
typedef long long LL;
struct X{
	LL A;
	LL B;
};
int main(int argc, char* argv[])
{
	LL N,K,i;
	cin>>N>>K;
	vector<X> AB(N);
	LL A1,B1;
	for (i=0;i<N;i++){
		cin>>AB[i].A>>AB[i].B;
	}
	LL k=0;
	LL M=1;
	while (true){
		for (i=0;i<N;i++){
			if (M>=AB[i].A && M<=AB[i].B){
				k++;
			}
			if (k==K){
				cout<<M<<endl;
				return 0;
			}
		}
		M++;
	}
	return 0;
}