看来必须开long

#include<bits/stdc++.h>
using namespace std;
long a[100005],b[100005],c[200005];
bool cmp(long a,long b){return a > b;}
int main(){
    long n,m; cin >> n >> m;
    for(int i = 1;i <= n;i++) cin >> a[i];
    for(int i = 1;i <= m;i++) cin >> b[i];
    for(int i = 1;i <= n;i++) c[i] = a[i];
    for(int i = 1;i <= m;i++) c[n + i] = b[i];
    sort(c + 1,c + n + m + 1,cmp);
    long ans = 0;
    for(int i = 1;i <= n;i++) ans += c[i];
    if(b[m] < c[n]){
        ans -= c[n];
        ans += b[m];
    }
    cout << ans;
    return 0;
}