#include <bits/stdc++.h>
using namespace std;
const long long mxn = 1e6;
const int mod1 = 1e9 + 7;
const int mod2 = 998244353;
const long long inf = 1e18;
const double pi = 3.1415926535897932384626;
long long binpow(long long a, long long b) {
  long long res = 1;
  while (b > 0) {
    if (b & 1) res = res * a;
    a = a * a;
    b >>= 1;
  }
  return res;
}
long long mpow(long long a, long long b, long long m) {
  a %= m;
  long long res = 1;
  while (b > 0) {
    if (b & 1) res = res * a % m;
    a = a * a % m;
    b >>= 1;
  }
  return res;
}
long long inv(long long a, long long m) { return mpow(a, m - 2, m); }
long long gcd(long long a, long long b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
long long ncr(long long n, long long k) {
  if (n < k) return 0;
  long long C[n + 1][k + 1];
  long long i, j;
  for (i = 0; i <= n; i++) {
    for (j = 0; j <= min(i, k); j++) {
      if (j == 0 || j == i)
        C[i][j] = 1;
      else
        C[i][j] = (C[i - 1][j - 1] + C[i - 1][j]);
    }
  }
  return C[n][k];
}
void solve() {
  int n, k, x;
  cin >> n >> k >> x;
  int c = k * x;
  int p = n - k;
  int a[n], sum = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  for (int i = 0; i < p; i++) {
    sum += a[i];
  }
  cout << sum + c;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  clock_t start, end;
  start = clock();
  solve();
  end = clock();
  double time_taken = double(end - start) / double(CLOCKS_PER_SEC);
  cerr << "\nTime : " << fixed << time_taken << setprecision(5) << " s \n";
  return 0;
}
