f[24][24];
g[1<<24];
d,i,j,k,n;
main(){
	scanf("%d",&n);
	for(j=0;j<n;++j){
		for(i=0;i<n;++i){
			scanf("%d",&f[j][i]);
		}
	}
	for(k=1;k<1<<n;++k){
		if(!__builtin_parity(k)){
			for(i=j=ffs(k)-1;++i<n;){
				if(k&1<<i){
					d=g[k^1<<j^1<<i]+f[j][i];
					if(g[k]<d)g[k]=d;
				}
			}
		}
	}
	printf("%d",g[(1<<n)-1]);
}