#include <iostream>
#include <cstring> 
#include <map>
#include <vector>
#include <queue>
#include <cmath>
#include <algorithm>
#include <set>
// #include <bits/stdc++.h>

// #define int long long
#define For(i,a,b) for(int i=(a);i<=(b);i++)
#define Rof(i,a,b) for(int i=(a);i>=(b);i--)
#define Grf(it,u,to) for(int it=he[u],to;(to=e[it],it);it=nxt[it]) 
#define In __inline 
#define OP operator
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
namespace Mine {
	// mt19937_64 wql(514);
	In ll read() {
		ll x=1,a=0;
		char ch=getchar();
		while(ch>'9' || ch<'0') x=(ch=='-')?-1:x,ch=getchar();
		while(ch>='0' && ch<='9') a=(a<<1)+(a<<3)+(ch-'0'),ch=getchar();
		return a*x;
	} const int N=21,M=1e6+100;
	int a[N][M],t[M],f[(1<<N)+1000];
	signed main() {
		int n=read(),m=read(),tot=0;
		For(i,0,n-1) For(j,1,m) {a[i][j]=read();if(a[i][j]!=-1) tot+=a[i][j];}
		if(n>14) printf("%d",tot);
		For(i,0,n-1) For(j,1,m) if(a[i][j]!=-1) t[j]|=(1<<i);
		For(i,0,n-1) For(j,1,m) if(a[i][j]!=-1) f[t[j]]+=a[i][j],f[t[j]^(1<<i)]-=a[i][j];
		For(i,0,n-1) For(S,0,(1<<n)-1) if(S>>i & 1) f[S^(1<<i)]+=f[S];
		int ans=0;
		For(S,0,(1<<n)-1) ans=max(ans,f[S]);
		return printf("%d",ans),0;
	}
}signed main() {
	// freopen("homework.in","r",stdin);
	// freopen("homework.out","w",stdout);
	return Mine::main();
}