#include <bits/stdc++.h>

using namespace std;
using ll = long long;
#define int ll
using VI = vector<int>;
using VVI = vector<VI>;
using PII = pair<int, int>;

#define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) x.begin(), x.end()
#define PB push_back

const ll LLINF = (1LL<<60);
const int INF = (1LL<<30);
const int MOD = 1000000007;

template <typename T> T &chmin(T &a, const T &b) { return a = min(a, b); }
template <typename T> T &chmax(T &a, const T &b) { return a = max(a, b); }
template <typename T> bool IN(T a, T b, T x) { return a<=x&&x<b; }
template<typename T> T ceil(T a, T b) { return a/b + !!(a%b); }
template<class S,class T>
ostream &operator <<(ostream& out,const pair<S,T>& a){
  out<<'('<<a.first<<','<<a.second<<')';
  return out;
}
template<class T>
ostream &operator <<(ostream& out,const vector<T>& a){
  out<<'[';
  REP(i, a.size()) {out<<a[i];if(i!=a.size()-1)out<<',';}
  out<<']';
  return out;
}

int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0};

int n, m;
int card[2][55];
bool used[55][55][105][2][5];
int dp[55][55][105][2][5];
int func(int x, int y, int s, int turn, int type) {
  if(used[x][y][s][turn][type]) return dp[x][y][s][turn][type];
  // cout << "in:" << x << " " << y << " " << s << " " << turn << " " << type << endl;

  // 1pのターン
  if(turn == 0) {
    int ret = -INF;
    // スタックに置く
    if(x != n) chmax(ret, func(x+1, y, s+1, !turn, 0));
    // パス
    if(type == 4) chmax(ret, 0LL);
    else if(type == 3) chmax(ret, func(x, y, 0, !turn, 4));
    else if(type == 2) chmax(ret, func(x, y, 0, !turn, 3));
    else {
      int score = 0, idx1 = x-1, idx2 = y-1;
      bool flag1 = false, flag2 = false;
      while(s > 0) {
        if(type == 0) {
          if(card[type][idx1] == -1) flag2 = true;
          else if(!flag1) score += card[type][idx1];
          idx1--;
        } else if(type == 1) {
          if(card[type][idx2] == -1) flag1 = true;
          else if(!flag2) score -= card[type][idx2];
          idx2--;
        }
        type = !type;
        s--;
      }
      chmax(ret, func(x, y, 0, !turn, 2) + score);
    }
    used[x][y][s][turn][type] = true;
    return dp[x][y][s][turn][type] = ret;
  }
  else {
    int ret = INF;
    // スタックに置く
    if(y != m) chmin(ret, func(x, y+1, s+1, !turn, 1));
    // パス
    if(type == 4) chmin(ret, 0LL);
    else if(type == 3) chmin(ret, func(x, y, 0, !turn, 4));
    else if(type == 2) chmin(ret, func(x, y, 0, !turn, 3));
    else {
      int score = 0, idx1 = x-1, idx2 = y-1;
      bool flag1 = false, flag2 = false;
      while(s > 0) {
        if(type == 0) {
          if(card[type][idx1] == -1) flag2 = true;
          else if(!flag1) score += card[type][idx1];
          idx1--;
        } else if(type == 1) {
          if(card[type][idx2] == -1) flag1 = true;
          else if(!flag2) score -= card[type][idx2];
          idx2--;
        }
        s--;
        type = !type;
      }
      chmin(ret, func(x, y, 0, !turn, 2) + score);
    }
    used[x][y][s][turn][type] = true;
    return dp[x][y][s][turn][type] = ret;
  }
}

signed main(void)
{
  cin.tie(0);
  ios::sync_with_stdio(false);

  cin >> n >> m;
  REP(i, n) cin >> card[0][i];
  REP(i, m) cin >> card[1][i];

  cout << func(0, 0, 0, 0, 2) << endl;

  return 0;
}



Measured memory_bytes: 16540