#include <bits/stdc++.h>
using namespace std;const int N = 110;
typedef pair<int, int>  PII;int n, m;
int g[N][N], d[N][N];int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};void bfs() {queue<PII> q;q.push({0, 0});d[0][0] = 0;while(q.size()) {auto t = q.front(); q.pop();int x = t.first, y = t.second;for (int i = 0; i < 4; i ++ ) {int a = x + dx[i], b = y + dy[i];if (a >= 0 && a < n && b >= 0 && b < m && !d[a][b] && !g[a][b]) {d[a][b] = d[x][y] + 1;q.push({a, b});}} } 
}int main() {cin >> n >> m;for (int i = 0; i < n; i ++ ) {for (int j = 0; j < m; j ++ ) {cin >> g[i][j];}}bfs();cout << d[n-1][m-1];return 0;
}

#include <bits/stdc++.h>
using namespace std;string s;
string t;
unordered_map<string, int> d;int dx[4] = {0, 0, 1, -1};
int dy[4] = {1, -1, 0, 0};int bfs(string s) {queue<string> q;string end = "12345678x";q.push(s);while(q.size()) {auto t = q.front(); q.pop();if (t == end) return d[t];int dist = d[t];int k = t.find("x");int x = k / 3, y = k % 3;for (int i = 0; i < 4; i ++ ) {int a = x + dx[i], b = y + dy[i];if (a >= 0 && a < 3 && b >=0 && b < 3) {swap(t[a *3 + b], t[k]);if (!d.count(t)) {d[t] = dist + 1;q.push(t);}swap(t[a * 3 + b], t[k]);}}}return -1;
}int main() {for (int i = 1; i <= 9; i ++ ) {cin >> t;s += t;}cout <<  bfs(s);return 0;
}

#include <bits/stdc++.h>
using namespace std;string s, str;
unordered_map<string, int> d;int dx[] = {-1, 1, 0, 0};
int dy[] = {0, 0, -1, 1};char op[] = "udlr";unordered_map<string, pair<string, char> >pre;int bfs() {queue<string> q;q.push(str);d[str] = 0;string end = "12345678x";while(q.size()) {auto t = q.front(); q.pop();if(t == end) return d[t];string s = t;int k = t.find('x');int x = k/3, y = k%3;for(int i=0; i<4; i++) {int a = x + dx[i], b = y + dy[i];if(a>=0 && a<3 && b>=0 && b<3) {swap(t[a*3+b], t[k]);if(!d.count(t)) {pre[t] = {s, op[i]};d[t] = d[s] + 1;q.push(t);}swap(t[a*3+b], t[k]);}}}return -1;
}int main() {for(int i=0; i<9; i++) {cin >> s;str += s;}int t = bfs();if(t!=-1) {string res;string end = "12345678x";while(1) {string t = pre[end].first;res += pre[end].second;if(t == str) break;end = t;}reverse(res.begin(), res.end());cout << res;} else {cout << "unsolvable";}// cout << t;return 0;
}

#include <bits/stdc++.h>
using namespace std;const int N = 1e5 + 10;vector<int> G[N];int n, m;int d[N];int bfs() {memset (d, -1, sizeof d);queue<int> q;q.push(1);d[1] = 0;while(q.size()) {auto t = q.front(); q.pop();for (auto j : G[t]) {if (d[j] == -1) {d[j] = d[t] + 1;q.push(j);}}}return d[n];
}int main() {cin >> n >> m;for (int i = 0; i < m; i ++ ) {int a, b;cin >> a >> b;G[a].push_back(b);}cout << bfs();return 0;
}