#include <iostream>
#include <queue>
#include <cstring>
using namespace std;
const int N = 1e3 + 10;
struct node {
	int I, J;
};
int n, m;
int a[N][N];
bool vis[N][N];
int x[4] = {-1, 1, 0, 0};
int y[4] = {0, 0, -1, 1};
bool check (int mid) {
	memset(vis, false, sizeof(vis));
	queue <node> q;
	q.push({1, 1});
	vis[1][1] = true;
	while (!q.empty()) {
		node t = q.front();
		q.pop();
		for (int i = 0; i < 4; i ++) {
			int X = x[i] + t.I;
			int Y = y[i] + t.J;
			if (X <= 0 || Y <= 0 || X > n || Y > m || vis[X][Y] || mid < a[X][Y]) continue;
			q.push({X, Y});
			vis[X][Y] = true;
			if (X == n) return true;
		}
	} return false;
}
int main () {
	cin >> n >> m;
	for (int i = 1; i <= n; i ++) {
		for (int j = 1; j <= m; j ++) {
			cin >> a[i][j];
		}
	}
	int l = 0, r = 1e9;
	int mid;
	while (l <= r) {
		mid = r + l >> 1;
		if (check(mid)) r = mid - 1;
		else l = mid + 1;
	} cout << mid;
	return 0;
}