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

//高速化 
struct ponjuice{ponjuice(){cin.tie(0);ios::sync_with_stdio(0);cout<<fixed<<setprecision(20);}}PonJuice;
//#define endl '\n' //インタラクティブ問題の時は消す

//型
using ll = long long;
using ld = long double;
using mint = modint998244353;//1000000007;
template<class T>using vc = vector<T>; template<class T>using vvc = vc<vc<T>>; template<class T>using vvvc = vvc<vc<T>>;
using vi = vc<int>;  using vvi = vvc<int>;  using vvvi = vvvc<int>;
using vl = vc<ll>;   using vvl = vvc<ll>;   using vvvl = vvvc<ll>;
using pi = pair<int, int>;  using pl = pair<ll, ll>;
using ull = unsigned ll;
template<class T>using priq = priority_queue<T>;
template<class T>using priqg = priority_queue<T, vc<T>, greater<T>>;

// for文
#define overload4(a, b, c, d, e, ...) e
#define rep1(n)             for(ll i = 0; i < n; i++)
#define rep2(i, n)          for(ll i = 0; i < n; i++)
#define rep3(i, a, b)       for(ll i = a; i < b; i++)
#define rep4(i, a, b, step) for(ll i = a; i < b; i+= step)
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)
#define per1(n)             for(ll i = n-1; i >= 0; i--)
#define per2(i, n)          for(ll i = n-1; i >= 0; i--)
#define per3(i, a, b)       for(ll i = b-1; i >= a; i--)
#define per4(i, a, b, step) for(ll i = b-1; i >= a; i-= step)
#define per(...) overload4(__VA_ARGS__, per4, per3, per2, per1)(__VA_ARGS__)
#define fore1(a)       for(auto&& i : a)	
#define fore2(i,a)     for(auto&& i : a)
#define fore3(x,y,a)   for(auto&& [x, y] : a)
#define fore4(x,y,z,a) for(auto&& [x, y, z] : a)
#define fore(...) overload4(__VA_ARGS__, fore4, fore3, fore2, fore1)(__VA_ARGS__)

//関数
#define mp make_pair
#define mt make_tuple
#define a first
#define b second
#define pb emplace_back
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define si(x) (ll)(x).size()
template<class S, class T>inline bool chmax(S& a, T b){return a < b && ( a = b , true);}
template<class S, class T>inline bool chmin(S& a, T b){return a > b && ( a = b , true);}
template<class T>void uniq(vc<T>&a){sort(all(a));a.erase(unique(all(a)),a.end());}
template<class T>vc<T> operator++(vc<T>&v,signed){auto res = v;fore(e,v)e++;return res;}
template<class T>vc<T> operator--(vc<T>&v,signed){auto res = v;fore(e,v)e--;return res;}
template<class T>vc<T> operator++(vc<T>&v){fore(e,v)e++;return v;}
template<class T>vc<T> operator--(vc<T>&v){fore(e,v)e--;return v;}

//入出力(operator)
template<int T>istream&operator>>(istream&is,static_modint<T>&a){ll v;is>>v;a=v;return is;}
istream&operator>>(istream&is,modint&a){ll v;cin>>v;a=v;return is;}
template<class S,class T>istream&operator>>(istream&is,pair<S,T>&a){is>>a.a>>a.b;return is;}
template<class T>istream&operator>>(istream&is,vc<T>&a){fore(e,a)is>>e;return is;}

template<int T>ostream&operator<<(ostream&os,static_modint<T>a){return os<<a.val();}
ostream&operator<<(ostream&os,modint a){return os<<a.val();}
template<class S,class T>ostream&operator<<(ostream&os,pair<S,T>&a){return os<<a.a<<" "<<a.b;}
template<class T>ostream&operator<<(ostream&os,set<T>&a){fore(it,a){os<<it<<" ";}return os;}
template<class T>ostream&operator<<(ostream&os,multiset<T>&a){fore(it,a){os<<it<<" ";}return os;}
template<class S,class T>ostream&operator<<(ostream&os,map<S,T>&a){fore(x,y,a){os<<x<<" "<<y<<"\n";}return os;}
template<class T>ostream&operator<<(ostream&os,unordered_set<T>&a){fore(it,a){os<<it<<" ";}return os;}
template<class S,class T>ostream&operator<<(ostream&os,unordered_map<S,T>&a){fore(x,y,a){os<<x<<" "<<y<<"\n";}return os;}
template<class T>ostream&operator<<(ostream&os,vc<T>&a){fore(e,a)os<<e<<" ";return os;}
template<class T>ostream&operator<<(ostream&os,vvc<T>&a){fore(e,a)os<<e<<"\n";return os;}

//入出力(関数)
vi readvi(ll n){vi a(n);cin>>a;return a;}
vl readvl(ll n){vl a(n);cin>>a;return a;}
vvi readg(ll n,ll m,bool bidirected=true){vvi g(n);rep(i,m){ll a,b;cin>>a>>b;a--;b--;g[a].pb(b);if(bidirected)g[b].pb(a);}return g;}
vvc<pi>readgc(ll n,ll m,bool bidirected=true){vvc<pi> g(n);rep(i,m){ll a,b,c;cin>>a>>b>>c;a--;b--;g[a].pb(b,c);if(bidirected)g[b].pb(a,c);}return g;}
vvi readt(ll n,bool bidirected=true){return readg(n,n-1,bidirected);}
vvc<pi> readtc(ll n,bool bidirected=true){return readgc(n,n-1,bidirected);}

inline void yes(){cout << "Yes\n";}
inline void no(){cout << "No\n";}
inline void yesno(bool y = true){if(y)yes();else no();}
inline void print(){cout<<endl;}
template<class T>inline void print(T a){cout<<a<<endl;}
template<class T,class... Ts>inline void print(T a,Ts ...b){cout<<a;(cout<<...<<(cout<<' ',b));cout<<endl;}

//定数
constexpr ll mod = 998244353;
constexpr ll minf=-(1<<29);
constexpr ll MINF=-(1LL<<60);
constexpr ll INF=(1LL<<60);
constexpr ld EPS = 1e-8;
const ld PI = acosl(-1);
#define equals(a, b) (abs((a) - (b)) < EPS)
const int dx[4] ={-1, 0, 1, 0};
const int dy[4] ={ 0, 1, 0,-1};
const int dx8[8] ={-1,-1,-1, 0, 1, 1, 1, 0};
const int dy8[8] ={-1, 0, 1, 1, 1, 0,-1,-1};

void solve();
int main() {
	int t = 1;
    // cin >>t;
    while(t--)solve();
}
#include <algorithm>

using ll = long long;
using namespace std;

const static ll inf = 1e18L;
class LiChaoTree {

  struct Line {
    ll a, b;

    Line(ll a, ll b) : a(a), b(b) {}
    Line() : a(0), b(0) {}

    inline ll f(ll x) const {
      return a * x + b;
    }

    Line& operator+=(const Line &ln) {
      if (b >= inf || ln.b >= inf) {
        a = 0; b = inf;
      } else {
        a += ln.a;
        b += ln.b;
      }
      return *this;
    }

    bool operator==(const Line &ln) const {
      return a == ln.a && b == ln.b;
    }
  };

  const Line line_inf = Line{0, inf};
  const Line line_zero = Line{0, 0};

  struct Node {
    Node *left, *right;
    Line line, lazy;

    Node(Line line) : left(nullptr), right(nullptr), line(line) {}
  };

  Node *root;
  ll xl, xr;

  inline bool compare(Line &l0, Line &l1, ll x) const {
    return l0.f(x) <= l1.f(x);
  }

  inline void _push_line(Node *nd, ll l, ll r) {
    if (nd == nullptr || nd->line == line_inf) return;

    ll m = (l + r) / 2;
    nd->left = _add_line(nd->left, nd->line, l, m);
    nd->right = _add_line(nd->right, nd->line, m, r);
    nd->line = line_inf;
  }

  inline void _add_lazy(Node *nd, Line &line) {
    if (nd == nullptr) return;

    nd->line += line;
    nd->lazy += line;
  }

  inline void _push_lazy(Node *nd, ll l, ll r) {
    if (nd == nullptr || nd->lazy == line_zero) return;

    _add_lazy(nd->left, nd->lazy);
    _add_lazy(nd->right, nd->lazy);
    nd->lazy = line_zero;
  }

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

    ll m = (l + r) / 2;
    if (nd == nullptr) return new Node(line);

    _push_lazy(nd, l, r);

    bool left = compare(line, nd->line, l);
    bool mid = compare(line, nd->line, m);
    bool right = compare(line, nd->line, r);
    if (mid) {
      swap(nd->line, line);
    }
    if(r-l > 1 && left != right) {
      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_val(ll a, ll b, Node *nd, Line &line, ll l, ll r) {
    if (r <= a || b <= l) {
      return nd;
    }

    if (a <= l && r <= b) {
      _add_lazy(nd, line);
      return nd;
    }

    _push_lazy(nd, l, r);
    _push_line(nd, l, r);

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

    ll m = (l + r) / 2;
    nd->left = _add_val(a, b, nd->left, line, l, m);
    nd->right = _add_val(a, b, 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);
    }

    _push_lazy(nd, l, r);

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

    ll m = (l + r) / 2;
    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_min(ll k, ll l, ll r) {
    Node *nd = root;
    ll s = inf;
    while (r - l > 0 && nd != nullptr) {
      ll m = (l + r) / 2;

      _push_lazy(nd, l, r);

      s = min(s, nd->line.f(k));
      if (k < m) {
        r = m;
        nd = nd->left;
      } else {
        l = m;
        nd = nd->right;
      }
    }
    return s;
  }

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

  // a_i <- min(a_i, a*i + b) for i in [xl, xr)
  void add_line(ll a, ll b) {
    Line line = Line{a, b};
    root = _add_line(root, line, xl, xr);
  }

  // a_i <- min(a_i, a*i + b) for i in [l, r)
  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);
  }

  // a_i <- a_i + (a*i + b) for i in [l, r)
  void add_val(ll a, ll b, ll l, ll r) {
    Line line = Line{a, b};
    root = _add_val(l, r, root, line, xl, xr);
  }

  // a_i <- +∞ for i in [l, r)
  void reset_val(ll l, ll r) {
    Line line = line_inf;
    root = _add_val(l, r, root, line, xl, xr);
  }

  // get a_i
  ll query_min(ll x) {
    return _query_min(x, xl, xr);
  }
};

void solve(){
    int n,m;
    cin>>n >> m;
    vl a = readvl(n);
    vl b = readvl(m);
    vl c = readvl(m);
    vl z = a;
    z.emplace_back(-1);
    rep(i,m){
        z.emplace_back(b[i]);
    }
    vi za = z_algorithm(z);

    LiChaoTree tree(0, m+1);
    tree.add_segment_line(0,0,0,1);
    rep(i,m){
        ll cost = tree.query_min(i);
        tree.add_segment_line(c[i],(cost-c[i]*i),i,i+za[n+1+i]+1);
    }

    print(tree.query_min(m)==inf?-1:tree.query_min(m));
}