#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;

typedef modint998244353 mint;
typedef long long ll;

// https://tjkendev.github.io/procon-library/cpp/convex_hull_trick/li_chao_tree_dynamic.html
class LiChaoTree {
  struct Line {
    ll a, b;
    ll f(ll x) const { return a*x + b; }
    Line(ll a, ll b) : a(a), b(b) {}
  };
  struct Node {
    Node *left, *right;
    Line line;

    Node(Line line) : left(nullptr), right(nullptr), line(line) {}
  };
  const ll inf = 1e16L;
  const Line inf_line = Line{0, inf};

  Node* root;
  ll xl, xr;

  Node* _add_line(Node *nd, Line line, ll l, ll r) {
    if(l == r) return nullptr;

    ll m = (l + r) >> 1;
    if(nd == nullptr) return new Node(line);

    bool left = (line.f(l) <= nd->line.f(l));
    bool mid = (line.f(m) <= nd->line.f(m));
    bool right = (line.f(r) <= nd->line.f(r));
    if(left && right) {
      nd->line = line;
      return nd;
    }
    if(!left && !right) {
      return nd;
    }
    if(mid) {
      swap(nd->line, line);
    }
    if(left != mid) {
      nd->left = _add_line(nd->left, line, l, m);
    } else {
      nd->right = _add_line(nd->right, line, m, r);
    }
    return nd;
  }

  Node* _add_segment_line(ll a, ll b, Node *nd, Line line, ll l, ll r) {
    if(r <= a || b <= l) {
      return nd;
    }
    if(a <= l && r <= b) {
      return _add_line(nd, line, l, r);
    }

    if(nd == nullptr) {
      nd = new Node(inf_line);
    }

    ll m = (l + r) >> 1;
    nd->left = _add_segment_line(a, b, nd->left, line, l, m);
    nd->right = _add_segment_line(a, b, nd->right, line, m, r);
    return nd;
  }

  ll _query(ll k, ll l, ll r) {
    Node *nd = root;
    ll s = inf;
    while(r-l > 0 && nd != nullptr) {
      ll m = (l + r) >> 1;
      s = min(s, nd->line.f(k));
      if(k < m) {
        r = m;
        nd = nd->left;
      } else {
        l = m;
        nd = nd->right;
      }
    }
    return s;
  }

public:
  // [xl, xr)
  LiChaoTree(ll xl, ll xr) : xl(xl), xr(xr), root(nullptr) {}

  void add_line(ll a, ll b) {
    Line line = Line{a, b};
    root = _add_line(root, line, xl, xr);
  }

  void add_segment_line(ll a, ll b, ll l, ll r) {
    Line line = Line{a, b};
    root = _add_segment_line(l, r, root, line, xl, xr);
  }

  ll query(ll x) {
    return _query(x, xl, xr);
  }
};

// isprime
bool isprime(ll n){
	if (n == 1) return false;
	for (ll i = 2; i * i <= n; i++){
		if (n % i == 0) return false;
	}
	return true;
}


// importrandom
// don't forget randomjumon
// and also isprime
ll RandomMod(ll l, ll r){
	ll ret = l + rand() % (r - l);
	while (!isprime(ret)) ret = l + rand() % (r - l);
	return ret;
}

ll randrange(ll l, ll r){
	return l + rand() % (r - l);
}
// -----


// defcomp
template <typename T>
vector<T> compress(vector<T> &X) {
	vector<T> vals = X;
	sort(vals.begin(), vals.end());
	vals.erase(unique(vals.begin(), vals.end()), vals.end());
	return vals;
}
// -----

// importbisect
template <typename T>
int bisect_left(vector<T> &X, T v){
	return lower_bound(X.begin(), X.end(), v) - X.begin();
}

template <typename T>
int bisect_right(vector<T> &X, T v){
	return upper_bound(X.begin(), X.end(), v) - X.begin();
}
// -----


int main(){
	srand((unsigned)time(NULL));
	
	// Rolling Hash
	typedef dynamic_modint<0> mint1;
	typedef dynamic_modint<1> mint2;

	int mod1 = RandomMod(7e8, 1e9);
	int mod2 = RandomMod(7e8, 1e9);

	mint1::set_mod(mod1);
	mint2::set_mod(mod2);

	mint1 b1 = randrange(100, 200);
	mint2 b2 = randrange(100, 200);

	int MAX_m = 1000000;
	vector<mint1> b1l(MAX_m+1);
	b1l[0] = 1;
	for (int i=0; i<MAX_m; i++){
		b1l[i+1] = b1l[i] * b1;
	}

	vector<mint2> b2l(MAX_m+1);
	b2l[0] = 1;
	for (int i=0; i<MAX_m; i++){
		b2l[i+1] = b2l[i] * b2;
	}
	// -----
	
	int n, m; cin >> n >> m;
	vector<ll> a(n);
	vector<ll> b(m);
	vector<ll> c(m);
	vector<ll> over;
	for (int i=0; i<n; i++){
		cin >> a[i];
		over.push_back(a[i]);
	}
	for (int i=0; i<m; i++){
		cin >> b[i];
		over.push_back(b[i]);
	}
	for (int i=0; i<m; i++){
		cin >> c[i];
	}
	vector<ll> p = compress(over);

	vector<mint1> t1(n+1);
	vector<mint2> t2(n+1);
	{
		mint1 x1 = 0;
		mint2 x2 = 0;
		for (int i=0; i<n; i++){
			x1 = x1 * b1 + bisect_left(p, a[i]) + 1;
			x2 = x2 * b2 + bisect_left(p, a[i]) + 1;
			t1[i+1] = x1;
			t2[i+1] = x2;
		}
	}
	vector<mint1> u1(m+1);
	vector<mint2> u2(m+1);
	{
		mint1 x1 = 0;
		mint2 x2 = 0;
		for (int i=0; i<m; i++){
			x1 = x1 * b1 + bisect_left(p, b[i]) + 1;
			x2 = x2 * b2 + bisect_left(p, b[i]) + 1;
			u1[i+1] = x1;
			u2[i+1] = x2;
		}
	}
	
	vector<int> linemax(m);

	for (int i=0; i<m; i++){
		int ub = m+1;
		int lb = i;
		while (ub - lb > 1){
			int targ = (ub + lb) / 2;
			mint1 kt1 = t1[targ-i];
			mint2 kt2 = t2[targ-i];
			mint1 ku1 = u1[targ] - u1[i] * b1l[targ - i];
			mint2 ku2 = u2[targ] - u2[i] * b2l[targ - i];
			if (kt1 == ku1 && kt2 == ku2){
				lb = targ;
			}else{
				ub = targ;
			}
		}
		linemax[i] = lb;\
	}

	LiChaoTree lc(0, m+1);
	vector<ll> dp(m+1, 1e18);

	for (int i=0; i<m+1; i++){
		ll val = 0;
		if (i > 0){
			val = lc.query(i);
		}
		dp[i] = val;
		//cout << i << " " << val << endl;
		if (i < m && linemax[i] > i){
			lc.add_segment_line(c[i], dp[i] - i * c[i], i, linemax[i] + 1);
		}
	}

	if (dp[m] >= 1e16) cout << -1 << endl;
	else cout << dp[m] << endl;

}