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

typedef long long ll;
typedef unsigned long long ull;
typedef unsigned __int128 HASH;
typedef pair<int,int> pii;
typedef pair<ll, ll> pll;
typedef pair<ull, ull> pullull;
typedef pair<ll,int> plli;
typedef pair<double, int> pdbi;
typedef pair<int,pii> pipii;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<pii> vpii;
typedef vector<vector<int>> mat;

#define rep(i,n) for (int i=0;i<(n);i++)
#define rep2(i,a,b) for (int i=(a);i<(b);i++)
#define rrep(i,n) for (int i=(n);i>0;i--)
#define rrep2(i,a,b) for (int i=(a);i>b;i--)
#define pb push_back
#define fi first
#define se second
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()

const ll hmod1 = 999999937;
const ll hmod2 = 1000000000 + 9;
const ll INF = 1<<30;
const ll mod = 1000000000 + 7;
const int dx4[4] = {1, 0, -1, 0};
const int dy4[4] = {0, 1, 0, -1};
const int dx8[8] = {1, 1, 1, 0, 0, -1, -1, -1};
const int dy8[8] = {0, 1, -1, 1, -1, 0, 1, -1};
const double pi = 3.141592653589793;

//#define int long long
#define addm(X, Y) (X) = ((X) + ((Y) % mod) + mod) % mod

int n, m;
int a[55], b[55];
int dp[52][52][52][52][2][2];

int calc(int da, int db, int sa, int sb, int tn) {
    if (sa == 0 && sb == 0) return 0;
    int i = n - 1 - da;
    int j = m - 1 - db;
    bool checka = false, checkb = false;
    int ret = 0;
    if (sb == 0) {
        while (i > (n - 1 - da - sa)) {
            if (a[i] != -1) ret += a[i];
            i--;
        }
        return ret;
    }
    if (sa == 0) {
        while(j > (m - 1 - db - sb)) {
            if (b[j] != -1) ret -= b[j];
            j--;
        }
        return ret;
    }
    //cout << tn << " " << i << " " << n - 1 - da - sa << " " << j << " " << m - 1 - db - sb << endl;
    while (i > (n - 1 - da - sa) && j > (m - 1 - db - sb)) {
        if (tn == 1) {
            if (a[i] == -1) checkb = true;
            else if (!checka) ret += a[i];
            if (b[j] == -1) checka = true;
            else if (!checkb) ret -= b[j];
            i--; j--;
        }
        else {
            if (b[j] == -1) checka = true;
            else if (!checkb) ret -= b[j];
            if (a[i] == -1) checkb = true;
            else if (!checka) ret += a[i];
            i--; j--;
        }
    }
    if (!checka) {
        while (i > (n - 1 - da - sa)) {
            if (a[i] != -1) ret += a[i];
            i--;
        }
    }
    if (!checkb) {
        while (j > (m - 1 - db - sb)) {
            if (b[j] != -1) ret -= b[j];
            j--;
        }
    }
    return ret;
}

int dfs(int da, int db, int sa, int sb, int tn, int cnt) {
    if ((dp[da][db][sa][sb][tn][cnt] != INF) && (dp[da][db][sa][sb][tn][cnt] != -INF)) return dp[da][db][sa][sb][tn][cnt];
    if (da == 0 && db == 0) {
        if (tn == 0) return (dp[da][db][sa][sb][tn][cnt] = max(dp[da][db][sa][sb][tn][cnt], calc(da, db, sa, sb, tn)));
        else return (dp[da][db][sa][sb][tn][cnt] = min(dp[da][db][sa][sb][tn][cnt], calc(da, db, sa, sb, tn)));
    }
    if (da == 0 && tn == 0) {
        if (sa == 0 && sb == 0 && cnt == 1) return (dp[da][db][sa][sb][0][cnt] = max(0, dp[da][db][sa][sb][0][cnt]));
        if (sa == 0 && sb == 0) dp[da][db][sa][sb][0][cnt] = max(dp[da][db][sa][sb][0][cnt], dfs(da, db, 0, 0, 1, 1));
        else dp[da][db][sa][sb][0][cnt] = max(dp[da][db][sa][sb][0][cnt], calc(da, db, sa, sb, tn) + dfs(da, db, 0, 0, 1, 0));
        return dp[da][db][sa][sb][0][cnt];
    }
    else if (db == 0 && tn == 1) {
        if (sa == 0 && sb == 0 && cnt == 1) return (dp[da][db][sa][sb][1][cnt] = min(0, dp[da][db][sa][sb][1][cnt]));
        if (sa == 0 && sb == 0) dp[da][db][sa][sb][1][cnt] = min(dp[da][db][sa][sb][1][cnt], dfs(da, db, 0, 0, 0, 1));
        else dp[da][db][sa][sb][1][cnt] = min(dp[da][db][sa][sb][1][cnt], calc(da, db, sa, sb, tn) + dfs(da, db, 0, 0, 0, 0));
        return dp[da][db][sa][sb][1][cnt];
    }
    if (tn == 0) {
        dp[da][db][sa][sb][0][cnt] = max(dp[da][db][sa][sb][0][cnt], dfs(da - 1, db, sa + 1, sb, 1, 0));
        if (sa == 0 && sb == 0 && cnt == 1) return (dp[da][db][sa][sb][0][cnt] = max(0, dp[da][db][sa][sb][0][cnt]));
        int tmp = calc(da, db, sa, sb, tn);
        if (sa == 0 && sb == 0) dp[da][db][sa][sb][0][cnt] = max(dp[da][db][sa][sb][0][cnt], tmp + dfs(da, db, 0, 0, 1, 1));
        else dp[da][db][sa][sb][0][cnt] = max(dp[da][db][sa][sb][0][cnt], tmp + dfs(da, db, 0, 0, 1, 0));
        return dp[da][db][sa][sb][0][cnt];
    }
    else {
        dp[da][db][sa][sb][1][cnt] = min(dp[da][db][sa][sb][1][cnt], dfs(da, db - 1, sa, sb + 1, 0, 0));
        if (sa == 0 && sb == 0 && cnt == 1) return (dp[da][db][sa][sb][1][cnt] = min(0, dp[da][db][sa][sb][1][cnt]));
        int tmp = calc(da, db, sa, sb, tn);
        if (sa == 0 && sb == 0) dp[da][db][sa][sb][1][cnt] = min(dp[da][db][sa][sb][1][cnt], tmp + dfs(da, db, 0, 0, 0, 1));
        else dp[da][db][sa][sb][1][cnt] = min(dp[da][db][sa][sb][1][cnt], tmp + dfs(da, db, 0, 0, 0, 0));
        return dp[da][db][sa][sb][1][cnt];
    }
}

signed main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> n >> m;
    rep(i, n) cin >> a[i];
    rep(i, m) cin >> b[i];
    rep(i, n + 1)rep(j, m + 1)rep(k, n + 1)rep(l, m + 1)rep(o, 2) {
        dp[i][j][k][l][0][o] = -INF;
        dp[i][j][k][l][1][o] = INF;
    }
    cout << dfs(n, m, 0, 0, 0, 0) << endl;
}

Measured memory_bytes: 113216