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

#define FOR(i,a,b)  for(ll (i)=a;(i)<(b);++(i))
#define RFOR(i,a,b) for(ll (i)=a;(i)>=(b);--(i))
#define REP(i,n)    FOR(i,0,n)
#define RREP(i,n)   RFOR(i,n,0)
#define ALL(v)      v.begin(), v.end()
#define UNIQ(v)     sort(ALL(v)); v.erase(unique(ALL(v)), v.end())
#define BIT(n)      (1LL<<(n))
#define DEBUG(a)    cout << #a << " = " << a << endl

const ll inf = 1e15;
const ll mod = 1e9+7;

int dy[] = {0, 0, 1, -1};
int dx[] = {1, -1, 0, 0};


int main() {
    int N, K;
    vector<int> A, B;
    cin >> N >> K;
    REP(i, N) {
        int a, b;
        cin >> a >> b;
        A.push_back(a);
        B.push_back(b);
    }

    sort(A.begin(), A.end());
    sort(B.begin(), B.end());

    int count = 0;
    for (ll i = 1; i <= 1000000001; i++) {
        auto iter = upper_bound(ALL(A), i);
        auto iter2 = lower_bound(ALL(B), i);
        int inc_num = iter - A.begin();
        int dec_num = iter2 - B.begin();
        
        count += inc_num - dec_num;
        if (count >= K) {
            cout << i << endl;
            return 0;
        }
    }
}