#include<bits/stdc++.h>
#define el '\n'
#define fi first
#define sec second
#define ll long long
#define pb push_back
#define sz(v) (int)(v).size()
#define all(v) (v).begin(),v.end()
using namespace std;
const int maxn = (int)5e3;
const int maxm = (int)1e5;
int a[maxn + 5], c[maxm + 5];
int n, m;
void Input(){
cin >> n >> m;
for(int i = 1; i <= n; i++) cin >> a[i];
for(int i = 1; i <= m; i++) cin >> c[i];
sort(a + 1, a + n + 1);
for(int i = m - 1; i >= 1; i--) c[i] = min(c[i], c[i + 1]);
}
int dp[maxn + 5];
//dp[i] kq toi uu nhat khi xet den vi tri i
void Solve(){
dp[0] = 0;
for(int i = 1; i <= n; i++) dp[i] = c[a[i] - a[1] + 1];
for(int i = 1; i <= n; i++){
dp[i] = 1e9;
for(int j = 1; j <= i; j++){
int w = a[i] - a[j] + 1;
dp[i] = min(dp[i], dp[j - 1] + c[w]);
}
}
cout << dp[n];
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
Input();
Solve();
}
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