#include <bits/stdc++.h>
using namespace std;
void re() { vector<int> b(1e10); }
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  int n, k, x;
  cin >> n >> k >> x;
  vector<int> a(n);
  for (int i = 0; i < n; ++i) cin >> a[i];
  for (int i = 0; i < k; ++i) {
    a[n - i - 1] = x;
  }
  int sm = 0;
  for (int i = 0; i < n; ++i) sm += a[i];
  cout << sm;
}
