#include <cstdio>

#include <algorithm>

#include <string>

using namespace std;

typedef long long ll;

const int maxn=200003;

namespace IO {

    inline void setIO(string s) {

        string in=s+".in";

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

    }

};

struct Edge {

    int u,v;

    ll c;

}ed[maxn];

bool cmp(Edge a,Edge b) {

    return a.c < b.c;

}

int p[maxn],tag[maxn];

int find(int x) {

    return p[x]==x?x:p[x]=find(p[x]);

}

int main() {

    // IO::setIO("input");

    int n,m,i,j,edges=0;

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

    for(i=1;i<=n+m+1;++i) p[i]=i;

    for(i=1;i<=n;++i) for(j=1;j<=m;++j) {

        ++edges;

        scanf("%lld",&ed[edges].c),ed[edges].u=i,ed[edges].v=j+n;

    }

    sort(ed+1,ed+1+edges,cmp);

    ll ans=0;

    for(i=1;i<=edges;++i) {

        int x=ed[i].u,y=ed[i].v;

        ll val=ed[i].c;

        x=find(x),y=find(y);

        if(x==y && !tag[x]) tag[x]=1, ans+=val;

        else if(x!=y&&(!tag[x]||!tag[y])) ans+=val, p[x]=y, tag[y]|=tag[x];

    }

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

    return 0;

}