#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:1024000000,1024000000")
using namespace std;
const int inf = 0x3f3f3f3f;
int n, k, x, d;
int main() {
  while (~scanf("%d%d%d", &n, &k, &x)) {
    int sum = 0;
    for (int(i) = 1; (i) <= (n); (i)++) {
      scanf("%d", &d);
      sum += i <= n - k ? d : x;
    }
    printf("%d\n", sum);
  }
  return 0;
}
