#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N=1000+5;
int n,m,mid;
int p[N][N]; 
int dx[4]={0,1,0,-1};
int dy[4]={-1,0,1,0};
struct pos{
	int x,y;
};
int vis[N][N];
int bfs(int t) {
	queue<pos> q;
	vis[1][1]=1;
	q.push({1,1});
	while(!q.empty()) {
		pos u=q.front(),v;
		q.pop();
		for(int i=0;i<4;i++) {
			v.x=u.x+dx[i];
			v.y=u.y+dy[i];
			if(v.x<1||v.x>n||v.y<1||v.y>m) continue;
			if(vis[v.x][v.y]) continue;
			if(p[v.x][v.y]>t) continue;
			if(v.x==n) return 1;
			vis[v.x][v.y]=1;
			q.push({v.x,v.y});
		}
	}
	return 0;
} 
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);cout.tie(0);
	cin>>n>>m;
	for(int i=1;i<=n;i++) {
		for(int j=1;j<=m;j++) {
			scanf("%d",&p[i][j]);
		}
	}
	int l=0,r=1000,ans=1000;
	while(l<=r) {
		mid=(l+r)>>1;
		memset(vis,0,sizeof(vis));
		if(bfs(mid)) {
			r=mid-1;
			ans=mid;
		}
		else l=mid+1;
	}
	cout<<ans<<endl;
	return 0;
}