#include <bits/stdc++.h>
int main() {
  int n, k, x;
  int a[100];
  scanf("%d%d%d", &n, &k, &x);
  for (int i = 0; i < n; i++) scanf("%d", &(a[i]));
  for (int i = n - 1; k > 0; i--, k--) a[i] = x;
  int sum = 0;
  for (int i = 0; i < n; i++) sum += a[i];
  printf("%d\n", sum);
  return 0;
}
