#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, x, sum = 0;
  scanf("%d%d%d", &n, &k, &x);
  vector<int> v(n);
  for (int i = 0; i < n; i++) scanf("%d", &v[i]);
  for (int i = 0; i < n - k; i++) sum += v[i];
  printf("%d", sum + x * k);
}
