#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int k;
  cin >> k;
  int x;
  cin >> x;
  int* a;
  a = new int[n + 1];
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }
  int index;
  index = n;
  while (k > 0) {
    a[index] = x;
    index--;
    k--;
  }
  int sum;
  sum = 0;
  for (int i = 1; i <= n; i++) {
    sum = sum + a[i];
  }
  cout << sum;
  return 0;
}
