#include<bits/stdc++.h>
using namespace std;
int main(){
    /*
    axe = a[k-1]
    iza el axe akbar min x = tmam
    iza ado = ++counter
    iza ashar meno 3ady
    */
    int n, k, counter = 0, axe, s;
    cin >> n>> k;
    vector<int> v;
    for(int i =0; i < n; i++){
        cin >> s;
        v.push_back(s);
    }
    axe = v[k-1];
    sort(v.begin(), v.end());
    for(int i = k-2; i >=1; i--){
        if(axe == v[i])
        counter++;
        else if(v[i-1] == v[i] && axe - counter <= v[i])
        counter++;
            //cout << axe << " " << counter << endl;
    }
    cout << axe + counter;
}