#include <cstdio>#include <cstdlib>#include <cstring>#include <algorithm>#include <iostream>using namespace std;const int N = 20 ;bool map[N][N] ;char s[N+1] ;int num[1<<N] ;int a[N] , n , sta[N];int p[N+1] ;int main(){ num[0] = 0 ; for (int i = 1 ; i < (1<<20) ; i++) { int t=0,x=i; while (x){ t+=(x&1); x>>=1; } num[i] = t ; } while (scanf("%d",&n)==1 && n){ for (int i = 0 ; i < N ; i++) { scanf("%s",s); for (int j = 0 ; j < N ; j++) map[i][j] = (s[j] == '#') ; } for (int j = 0 ; j < N ; j++){ int mask = 0 ; for (int i = 0 ; i < N ; i++){ mask = (mask<<1 | map[i][j]) ; } sta[j] = mask ; } int ans = 0 ; for (int i = 1 ; i < (1<<20) ; i++){ if (num[i]>=n || n-num[i]>N) continue ; for (int j = 0 ; j <= N ; j++) p[j]=0 ; for (int j = 0 ; j < N ; j++){ int mask = sta[j] & i ; p[num[mask]]++ ; } int tmp=0 , last=n-num[i]; for (int j = 20 ; j >= 1 ; j--){ if (last>=p[j] && p[j]) { tmp += p[j]*j; last -= p[j] ; }else if (last<=p[j]){ tmp += j*last; break ; } } ans=max(ans,tmp) ; } printf("%dn",ans); } return 0 ;}
