#include<cstdio>
#include<algorithm>
using namespace std;
int m,n,a[200000],b[200000],ans;
int main(){
	scanf("%d %d",&m,&n);
	for(int i=1;i<=m;++i) scanf("%d",&b[i]);
	for(int i=1;i<=n;++i) scanf("%d",&a[i]);
	sort(b+1,b+1+n);
	for(int i=1;i<=n;++i){
		int l=1,r=m;
		while(l<=r){
			int mid=(l+r)>>1;
			if(a[i]<=b[mid]) l=mid+1;
			else r=mid-1;
		}
		ans+=b[l];
	}
	printf("%d",ans);
	return 0;
}