#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<vector>
using namespace std;
const int INF=0x3f3f3f3f;
#define mem(x,y) memset(x,y,sizeof(x))
#define SI(x) scanf("%d",&x)
#define PI(x) printf("%d",x)
#define SD(x) scanf("%lf",&x)
#define P_ printf(" ")
typedef long long LL;
const int MAXN=10010;
double dp[2][110],a[MAXN],b[MAXN];
int cmp(const void *a,const void *b)
{
    return *(double *)a < *(double *)b ? 1 : -1;
}
int main(){
    int n,m;
    while(~scanf("%d%d",&n,&m),n||m){
        if(n<=m){
            for(int i=1;i<=n;i++)SD(a[i]);
            for(int i=1;i<=m;i++)SD(b[i]);
        }
        else{
            swap(n,m);
            for(int i=1;i<=m;i++)SD(b[i]);
            for(int i=1;i<=n;i++)SD(a[i]);
        }
        qsort(a+1,n,sizeof(a[1]),cmp);
        qsort(b+1,m,sizeof(b[1]),cmp);
        int len=m-n+1;
        mem(dp,0);
        for(int i=1;i<=n;i++){
            dp[i%2][1]=dp[(i-1)%2][1]+abs(a[i]-b[i]);
            for(int k=2;k<=len;k++){
                int j=i+k-1;
                dp[i%2][k]=min(dp[(i-1)%2][k]+abs(a[i]-b[j]),dp[i%2][k-1]);
            }
        }
        printf("%.6lf\n",dp[n%2][len]);
    }
    return 0;
}