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