#include<bits/stdc++.h> using namespace std; #define int long long #define pii pair<int,int> #define fr first #define sc second #define mk make_pair int read(){int x=0,f=1;char c=getchar();while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}while(c>='0'&&c<='9')x=x*10+c-'0',c=getchar();return x*f;} const int MAXN=100010; int n,k,sum,ans,a[MAXN]; void slv(){ n=read(),k=read(); for(int i=1;i<=n;i++)sum+=a[i]=read(); if(k==1){ printf("0"); return; } ans=sum; for(int i=1;i<=k;i++){ int res=0; for(int j=i;j<=n;j+=k){ res+=a[j]; } ans=min(ans,sum-res); } printf("%lld",ans); } signed main(){ slv(); return 0; }