#include<cstdio>

#include<iostream>

#include<cstring>

#include<cstdlib>

#include<algorithm>

#include<cmath>

using namespace std;

int n,m,a[][],bef[];

bool v[][];

bool check(int mid)

{

    memset(v,false,sizeof(v));

    for(int i=;i<=n;i++)

    {

        int last=;

        memset(bef,,sizeof(bef));

        for(int j=;j<=m;j++)

        {

            if(!(a[i][j]<mid))

            {

                for(int k=last;k;k=bef[k])

                {

                    if(v[k][j])return true;

                    v[k][j]=true;

                }

                bef[j]=last;

                last=j;

            }

        }

    }

    return false;

}

int main()

{

    freopen("a.in","r",stdin);

    freopen("a.out","w",stdout);

    int mmin=,mmax=;

    scanf("%d%d",&n,&m);

    for(int i=;i<=n;i++)

        for(int j=;j<=m;j++)

        {

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

            mmax=max(mmax,a[i][j]);

            mmin=min(mmin,a[i][j]);

        }

    int l=mmin,r=mmax,ans;

    while(l<=r)

    {

        int mid=(l+r)/;

        if(check(mid))

        {

            ans=mid;

            l=mid+;

        }

        else r=mid-;

    }

    printf("%d\n",ans);

    return ;

}