#include <bits/stdc++.h>
using namespace std;
int main() {
  vector<int> deals;
  int n, k, x, a;
  int sum = 0;
  cin >> n >> k >> x;
  deals.reserve(n);
  for (int i = 0; i < n; i++) {
    cin >> a;
    if (n - i <= k)
      deals.emplace_back(x);
    else
      deals.emplace_back(a);
  }
  for (int val : deals) sum += val;
  cout << sum;
}
