#include<iostream>
#include<cstring>
#include<algorithm>
#include<cstdio>

using namespace std;

const int N = 1010;

int n, m;
int g[N][N];
bool st[N][N];
int dx[] = {0,1,0}, dy[] = {1,0,-1};

bool dfs(int x, int y, int minv){
	if(x == n-1) return true;
	bool success = false;
	for(int k = 0; k < 3; k++){
		int a = x+dx[k], b = y+dy[k];
		if(a >= 0 && a < n && b >= 0 && b < m && !st[a][b] && g[a][b] <= minv){
			st[a][b] = true;
			if(dfs(a, b, minv)) return true;
		}
	}
	return success;
}

bool check(int mid){// 判断对于mid的伤害是否合法
	for(int i = 0; i < m; i++){// 枚举第一行的起点，每个点都需要走一遍
		memset(st, false, sizeof st);
		if(dfs(0, i, mid)) return true;
	}
	return false;
}

int main(){
	int maxv = 0; 
	scanf("%d%d", &n, &m);
	for(int i = 0; i < n; i++)
		for(int j = 0; j < m; j++){
			scanf("%d", &g[i][j]);
			maxv = max(maxv, g[i][j]);
		}
			
	int l = 0, r = maxv;
	while(l < r){
		int mid = (l+r)>>1;
		if(check(mid)) r = mid;
		else l = mid+1;
	}
	cout << l << endl;
	return 0;
}