#include<bits/stdc++.h>
using namespace std;
using P=pair<int,int>;
constexpr int INF=1e9;
struct edge{int to,cost;};
bool chmin(int&a,int b){return a>b?a=b,true:false;}
int main(){
  int H,W; cin>>H>>W;
  vector<vector<int>>A(H,vector<int>(W-1)),B(H-1,vector<int>(W));
  for(int i=0;i<H;i++)for(int j=0;j<W-1;j++)cin>>A[i][j];
  for(int i=0;i<H-1;i++)for(int j=0;j<W;j++)cin>>B[i][j];
  vector<vector<edge>>G(H*W);
  for(int i=0;i<H;i++)for(int j=0;j<W-1;j++)G[i*W+j].push_back({i*W+j+1,A[i][j]});
  for(int i=0;i<H;i++)for(int j=1;j<W;j++)G[i*W+j].push_back({i*W+j-1,A[i][j-1]});
  for(int i=0;i<H-1;i++)for(int j=0;j<W;j++)G[i*W+j].push_back({i*W+j+W,B[i][j]});
  for(int i=1;i<H;i++)for(int j=0;j<W;j++){
    for(int k=0;k<i;k++)G[i*W+j].push_back({k*W+j,i-k+1});
  }
  vector<int>dist(H*W,INF); dist[0]=0;
  priority_queue<P,vector<P>,greater<P>>Q; Q.push({0,0});
  while(!Q.empty()){
    auto[c,v]=Q.top(); Q.pop();
    if(dist[v]<c)continue;
    for(edge e:G[v])if(chmin(dist[e.to],c+e.cost))Q.push({dist[e.to],e.to});
  }
  cout<<dist[H*W-1]<<endl;
}
#include<bits/stdc++.h>
#define rep(i,a,...) for(int i = (a)*(strlen(#__VA_ARGS__)!=0);i<(int)(strlen(#__VA_ARGS__)?__VA_ARGS__:(a));++i)
#define per(i,a,...) for(int i = (strlen(#__VA_ARGS__)?__VA_ARGS__:(a))-1;i>=(int)(strlen(#__VA_ARGS__)?(a):0);--i)
#define foreach(i, n) for(auto &i:(n))
#define all(x) (x).begin(), (x).end()
#define bit(x) (1ll << (x))
#define lambda(RES_TYPE, ...) (function<RES_TYPE(__VA_ARGS__)>)[&](__VA_ARGS__) -> RES_TYPE
#define method(FUNC_NAME, RES_TYPE, ...) function<RES_TYPE(__VA_ARGS__)> FUNC_NAME = lambda(RES_TYPE, __VA_ARGS__)
using namespace std;
using ll = long long;
using pii = pair<int,int>;
using pll = pair<ll,ll>;
//const ll MOD = (ll)1e9+7;
const ll MOD = 998244353;
const int INF = (ll)1e9+7;
const ll INFLL = (ll)1e18;
template<class t>
using vvector = vector<vector<t>>;
template<class t>
using vvvector = vector<vector<vector<t>>>;
template<class t>
using priority_queuer = priority_queue<t, vector<t>, greater<t>>;
template<class t, class u> bool chmax(t &a, u b){if(a<b){a=b;return true;}return false;}
template<class t, class u> bool chmin(t &a, u b){if(a>b){a=b;return true;}return false;}
#ifdef DEBUG
#define debug(x) cout<<"LINE "<<__LINE__<<": "<<#x<<" = "<<x<<endl;
#else
#define debug(x) (void)0
#endif

namespace templates{
  ll modpow(ll x, ll b){
    ll res = 1;
    while(b){
      if(b&1)res = res * x % MOD;
      x = x * x % MOD;
      b>>=1;
    }
    return res;
  }

  ll modinv(ll x){
    return modpow(x, MOD-2);
  }

  bool was_output = false;
  template<class t>
  void output(t a){
    if(was_output)cout << " ";
    cout << a;
    was_output = true;
  }
  void outendl(){
    was_output = false;
    cout << endl;
  }
  ll in(){
    ll res;
    scanf("%lld", &res);
    return res;
  }

  template<class t>
  istream& operator>>(istream&is, vector<t>&x){
    for(auto &i:x)is >> i;
    return is;
  }

  template<class t, class u>
  istream& operator>>(istream&is, pair<t, u>&x){
    is >> x.first >> x.second;
    return is;
  }

  template<class t>
  t in(){
    t res; cin >> res; return res;
  }

  template<class t>
  void out(t x){
    cout << x;
  }

  template<class t>
  vector<t> sorted(vector<t> line,function<bool(t,t)> comp=[](t a,t b){return a<b;}){
    sort(line.begin(),line.end(),comp);
    return line;
  }

  template<class t>
  vector<t> reversed(vector<t> line){
    reverse(line.begin(),line.end());
    return line;
  }
}

using namespace templates;

ll func(){
    int n = in();
    int L = in();
    vector<ll> start(n);
    vector<ll> goal(n);
    foreach(i,start)i=in();
    foreach(i,goal)i=in();
    vector<ll> x(n+1);
    vector<ll> y(n+1);
    x[0] = start[0]-1;
    y[0] = goal[0]-1;
    x.back() = L - start.back();
    y.back() = L - goal.back();
    rep(i,1,n){
        x[i] = start[i]-start[i-1]-1;
        y[i] = goal[i]-goal[i-1]-1;
    }
    int last = 0;
    ll res = 0;
    rep(i,n+1){
        while(last < n + 1 and x[last]==0)++last;
        if(y[i]==0)continue;
        ll sum = 0;
        int itr = last;
        while(sum < y[i]){
            sum += x[itr++];
        }
        if(sum != y[i])return -1;
        if(last < i and i < itr){
            res += i - last;
            res += itr - i - 1;
        }else{
            res += max(abs(i-last),abs(i-(itr-1)));
        }
        last = itr;
    }
    return res;
}

int main(){
    cout << func() << endl;
  return 0;
}
