#include <iostream>
#include <iomanip>
#include <cstdio>
#include <string>
#include <cstring>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <cfloat>
#include <climits>
#include <ctime>
#include <cassert>
#include <numeric>
#include <functional>
using namespace std;

#define rep(i,a,n) for(int (i)=(a); (i)<(n); (i)++)
#define repq(i,a,n) for(int (i)=(a); (i)<=(n); (i)++)
#define repr(i,a,n) for(int (i)=(a); (i)>=(n); (i)--)
#define int long long int

template<typename T> void chmax(T &a, T b) {a = max(a, b);}
template<typename T> void chmin(T &a, T b) {a = min(a, b);}
template<typename T> void chadd(T &a, T b) {a = a + b;}

typedef pair<int, int> pii;
typedef long long ll;

int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};
constexpr ll INF = 1001001001001001LL;
constexpr ll MOD = 1000000007LL;

constexpr int S = 51;
int N, M, a[60], b[60];
int suma[60], sumb[60];
// memo[s][t][u][v][turn][pass] :=
//      a ??????????????????????????? [s, t) ????????????
//      b ??????????????????????????? [u, v) ????????????
//      turn ??¨ pass ????????±
//      ???????????? point_a - point_b ??????
int memo[S][S][S][S][2][3];

// pass ?????£?¶?????????????????????°?????????
int dfs(int s, int t, int u, int v, int turn, int pass) {
    int& val = memo[s][t][u][v][turn][pass];
    if(val != -INF) return val;

    // ???????????????????????¶?????§??????????????????
    val =  suma[t] - suma[s];
    val -= sumb[v] - sumb[u];

    // ???????????¶??§???????????° pass ??????
    // ?????????????????¨????????£??????????????????????????????
    // ??\??????????????§????????????????????????????????£?????????
    if(!(s == t && u == v && pass == 1)) {
        if(s == t && u == v) val += dfs(t, t, v, v, turn^1, pass+1);
        else val += dfs(t, t, v, v, turn^1, 0);
    }

    // take (first)
    if(turn == 0) {
        if(t < N) {
            // ??¨??? -> ?????¨?????????????????????????????????????????¨????????????????????????
            //      -> ???????????????????????????????????????????????¨??????
            if(a[t] == -1) chmax(val, dfs(s, t+1, v, v, turn^1, 0));
            else           chmax(val, dfs(s, t+1, u, v, turn^1, 0));
        }
    }
    // take (second)
    else {
        if(v < M) {
            if(b[v] == -1) chmin(val, dfs(t, t, u, v+1, turn^1, 0));
            else           chmin(val, dfs(s, t, u, v+1, turn^1, 0));
        }
    }
    return val;
}

signed main() {
    rep(i,0,S) rep(j,0,S) rep(k,0,S) rep(l,0,S) rep(t,0,2) rep(p,0,3)
        memo[i][j][k][l][t][p] = -INF;

    cin >> N >> M;
    rep(i,0,N) cin >> a[i];
    rep(i,0,M) cin >> b[i];

    // 1-indexed
    rep(i,0,N) suma[i+1] = (a[i] == -1 ? suma[i] : suma[i] + a[i]);
    rep(i,0,M) sumb[i+1] = (b[i] == -1 ? sumb[i] : sumb[i] + b[i]);
    cout << dfs(0, 0, 0, 0, 0, 0) << endl;
    return 0;
}