#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n, k, x, sum = 0;
  cin >> n >> k >> x;
  vector<int> v(n);
  for (auto &x : v) cin >> x;
  for (int i = 0; i < n - k; i++) {
    sum += v[i];
  }
  cout << k * x + sum << endl;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(nullptr);
  solve();
  return 0;
}
