#include<iostream> #include<vector> #include<string> #include<algorithm> #include<map> #include<set> #include<utility> #include<cmath> #include<cstring> #include<queue> #include<stack> #include<cstdio> #include<sstream> #include<iomanip> #include<assert.h> #define loop(i,a,b) for(int i=a;i<b;i++) #define rep(i,a) loop(i,0,a) #define pb push_back #define mt make_tuple #define all(in) in.begin(),in.end() #define shosu(x) fixed<<setprecision(x) using namespace std; //kaewasuretyuui typedef long long ll; typedef pair<int,int> pii; typedef vector<int> vi; typedef vector<vi> vvi; typedef vector<pii> vp; typedef vector<vp> vvp; typedef vector<string> vs; typedef vector<double> vd; typedef tuple<int,int,int> tp; typedef vector<tp> vt; typedef vector<vd> vvd; typedef pair<int,pii> pip; typedef vector<pip>vip; const double PI=acos(-1); const double EPS=1e-7; const int inf=1e8; const ll INF=1e16; int dx[]={0,1,0,-1}; int dy[]={1,0,-1,0}; int main(){ int n,m; cin>>n>>m; vi in(m); rep(i,m)cin>>in[i]; sort(all(in)); int out=inf; rep(i,m-n+1){ int l=in[i],r=in[i+n-1]; out=min(out,min(abs(r)+r-l,abs(l)+r-l)); } cout<<out<<endl; }