#include<iostream>

 #include<cstdio>

 #include<cstring>

 #include<algorithm>

 #include<queue>

 using namespace std;

 const int N=;

 int n,k,temp;

 int main(){

    scanf("%d%d",&n,&k);

      priority_queue<int>Q;

    for(int i=;i<=n;i++){

       scanf("%d",&temp);

       Q.push(temp);

    }

    int ans=,tt=k;

    while(Q.size()>k){

         tt=k;

       ans+=(Q.top()-);

       while(tt--)

         Q.pop();

    }

    if(Q.size()>)

      ans+=(Q.top()-);

    printf("%d\n",ans*);

 }