#include <bits/stdc++.h>
using namespace std;
int main() {
  unsigned short int n, k, x, a[100], time = 0;
  ios_base::sync_with_stdio(false);
  cin >> n >> k >> x;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  for (int i = 0; i < n - k; i++) {
    time += a[i];
  }
  cout << time + k * x;
  return 0;
}
