#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, x, a[111], sum = 0;
  cin >> n >> k >> x;
  for (int i = 1; i <= n; ++i) cin >> a[i], sum += a[i];
  for (int i = n; i >= n - k + 1; --i) sum -= a[i];
  sum += x * k;
  cout << sum << endl;
  return 0;
}
