#include<iostream>

#include<cstdio>

#include<cstring>

#include<algorithm>

#define ll long long

using namespace std;

const int N=1e5+;

int n,m,xnt,fa[N];

ll ans;

bool fx[N];

struct Ed{

    int x,y,w;

    Ed(int x=,int y=,int w=):x(x),y(y),w(w) {}

    bool operator< (const Ed &b) const

        {return w<b.w;}

}ed[N];

int rdn()

{

    int ret=;bool fx=;char ch=getchar();

    while(ch>''||ch<''){if(ch=='-')fx=;ch=getchar();}

    while(ch>=''&&ch<='') ret=(ret<<)+(ret<<)+ch-'',ch=getchar();

    return fx?ret:-ret;

}

void add(int x,int y,int z)

{

    ed[++xnt]=Ed(x,y,z);

}

int find(int a){return fa[a]==a?a:fa[a]=find(fa[a]);}

int main()

{

    n=rdn(); m=rdn();

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

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

        {

            w=rdn();

            add(i,j+n,w);

        }

    int d=n+m;

    for(int i=;i<=d;i++) fa[i]=i;

    sort(ed+,ed+xnt+);

    for(int i=,u,v;i<=xnt;i++)

    {

        u=find(ed[i].x); v=find(ed[i].y);

        if(u!=v&&(fx[u]&fx[v])==)

        {

            fa[u]=v; fx[v]|=fx[u]; ans+=ed[i].w;

        }

        else if(u==v&&!fx[u])

        {

            fx[u]=; ans+=ed[i].w;

        }

    }

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

    return ;

}