int r, c;

queue<pair<int, int>> q;

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

visited[0][0] = true;

dist[0][0] = 1;

while(!q.empty()) {

r = q.front().first;

c = q.front().second;

q.pop();

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

int nr = r + dr[k];

int nc = c + dc[k];

if(0 <= nr && nr < N && 0 <= nc && nc < M) {

if(maze[nr][nc] == 1 && visited[nr][nc] == false) {

visited[nr][nc] = true;

q.push(make_pair(nr, nc));

dist[nr][nc] = dist[r][c] + 1;

}

}

}

}

scanf("%d %d", &N, &M);

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

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

scanf("%1d", &maze[i][j]);

}

}

bfs();

printf("%d", dist[N-1][M-1]);

return 0;