int n = maps.size();

int m = maps[0].size();

vector<vector<int>> directions {{0, 1}, {1, 0}, {-1, 0}, {0, -1}};

queue<pair<int, int>> dq;

dq.push(make_pair(0, 0));

maps[0][0] = 1;

visited[0][0] = true;

while (!dq.empty()) {

pair<int, int> cur = dq.front();

dq.pop();

for (const vector<int>& direction : directions) {

int row = cur.first + direction[0];

int col = cur.second + direction[1];

if (row < 0 || row >= n || col < 0 || col >= m) {

continue;

}

if (maps[row][col] == 0) {

continue;

}

if (visited[row][col]) {

continue;

}

if (row == n - 1 && col == m - 1) {

return maps[cur.first][cur.second] + 1;

}

visited[row][col] = true;

maps[row][col] = maps[cur.first][cur.second] + 1;

dq.push(make_pair(row, col));

}

}

return -1;

}