#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int n,k;
	cin>>n>>k;
	vector<int>a(n+5);
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	int ans=0;
	for(int i=n-k+1;i<=n;i++){
		ans+=a[i];
	}
	cout<<ans;
}

#pragma GCC optimize ("O3")
#include <bits/stdc++.h>
using namespace std;
const long long nmax = 1e6 + 5;
long long a[nmax], n, k, s = 0;
int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);cout.tie(NULL);
  cin >> n >> k;
  for (long long i = 1; i <= n; ++i) cin >> a[i];
  reverse(a + 1, a + 1 + n);
  for (long long i = 1; i <= k; ++i) s += a[i];
  cout << s;
}