#include <bits/stdc++.h>
#define oi ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
using namespace std;
const int N = 1e6;
int n, m, sum=0, p=0;
int a[N], b[N];
int main()
{
  //freopen("xx.in", "r", stdin);
  //freopen("xx.out", "w",stdout);
  oi;
  cin>>n>>m;
    for(int i=0;i<n;i++)
        cin>>a[i];
        for(int i=0;i<m;i++)
        cin>>b[i];
      sort(a, a+m);
      sort(b, b+n);
    for(int i=0;i<n;i++){
        if(p<m&&b[i]>a[p]){
            p++;
            b[i]=0;
      }
    }
    if(p==m){
        for(int i=0;i<n;i++){
    if(b[i]>0)sum+=b[i];
    }
  }
    cout<<sum;
  return 0;
}

WA 爆0！！！