#include<iostream>

#include<cstdio>

#include<cstring>

#include<algorithm>

using namespace std;

typedef long long ll;

int const xn=2e5+;

int n,m,ct,fa[xn];

ll ans;

bool v[xn];

struct N{int u,v,w;}ed[xn<<];

bool cmp(N x,N y){return x.w<y.w;}

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

int rd()

{

    int ret=,f=; char ch=getchar();

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

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

    return f?ret:-ret;

}

int main()

{

    n=rd(); m=rd();

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

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

        {

            z=rd();

            ed[++ct].u=i; ed[ct].v=j+n; ed[ct].w=z;

        }

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

    sort(ed+,ed+ct+,cmp);

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

    {

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

        if(x==y)

        {

            if(v[x])continue;

            else ans+=w,v[x]=;

        }

        else

        {

            if(v[x]&&v[y])continue;

            else if(v[x]||v[y])ans+=w,fa[x]=y,v[y]=;

            else ans+=w,fa[x]=y;

        }

    }

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

    return ;

}