{

vector<vector<int>> dp;

for (int i = 0; i < land.size(); i++) {

dp.push_back(vector<int> (4, 0));

}

for (int i = 0; i < 4; i++) {

dp[0][i] = land[0][i];

}

for (int i = 1; i < land.size(); i++) {

for (int j = 0; j < 4; j++) {

for (int k = 0; k < 4; k++) {

if (j == k) {

continue;

}

dp[i][j] = max(dp[i][j], land[i][j] + dp[i - 1][k]);

}

}

}

int answer = 0;

for (int i = 0; i < 4; i++) {

answer = max(answer, dp[land.size() - 1][i]);

}

return answer;

}