#include //#include using namespace std; //using namespace atcoder; //using mint = modint1000000007; //const int mod = 1000000007; //using mint = modint998244353; //const int mod = 998244353; //const int INF = 1e9; const long long LINF = 1e18; #define rep(i, n) for (int i = 0; i < (n); ++i) #define rep2(i,l,r)for(int i=(l);i<(r);++i) #define rrep(i, n) for (int i = (n-1); i >= 0; --i) #define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i) #define all(x) (x).begin(),(x).end() #define allR(x) (x).rbegin(),(x).rend() #define endl "\n" #define P pair template inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n, m; cin >> n >> m; vectora(n); rep(i, n)cin >> a[i]; vectors(n); vectorok(n, 0); rep(i, n) { cin >> s[i]; rep(j, m) { if ('o' == s[i][j])ok[i] |= 1 << j; } } vectorzeta(1 << m); rep(i, n)zeta[ok[i]] += a[i]; rep(j, n) { rep(i, 1 << m) { if (1 & (i >> j)) { zeta[i] += zeta[i & ~(1 << j)]; } } } vectordp(1 << m, -LINF); dp[0] = 0; int bit = (1 << m) - 1; rep(i, 1 << m) { rep(j, m) { if (1 & (i >> j))continue; int ni = i + (1 << j); long long val = zeta[bit ^i] - zeta[bit - ni]; chmax(dp[i ^ (1 << j)], dp[i] + val * val); } } cout << dp[bit] << endl; return 0; }