#include <bits/stdc++.h>
using namespace std;
int a[105];
int main() {
  int n, k, x;
  scanf("%d%d%d", &n, &k, &x);
  for (int i = 0; i < n; ++i) scanf("%d", a + i);
  int ans = k * x;
  for (int i = 0; i < n - k; ++i) ans += a[i];
  printf("%d\n", ans);
}
