#include <bits/stdc++.h>
using namespace std;
int n, i, j, x, k, v[105], sol;
int main() {
  cin >> n >> k >> x;
  for (i = 1; i <= n; i++) cin >> v[i];
  sol += k * x;
  n = max(0, n - k);
  for (i = 1; i <= n; i++) sol += v[i];
  cout << sol << '\n';
  return 0;
}
