#include #include #include #include #include #include #include #include #include #include using namespace std; struct UnionFind { long long ngroup; vector par; vector siz; UnionFind(long long N) : par(N), siz(N) { ngroup = N; for(long long i = 0; i < N; i++){ par[i] = i; siz[i] = 1; } } long long root(long long x) { if (par[x] == x) return x; return par[x] = root(par[x]); } long long unite(long long x, long long y) { long long rx = root(x); long long ry = root(y); if (rx == ry) return rx; ngroup--; if (siz[rx] > siz[ry]) swap(rx, ry); par[rx] = ry; siz[ry] += siz[rx]; return ry; } bool same(long long x, long long y) { long long rx = root(x); long long ry = root(y); return rx == ry; } long long size(long long x){ return siz[root(x)]; } long long group_count(){ return ngroup; } }; const long long m = 998244353; long long mod_exp(long long b, long long e){ if (e > 0 && b == 0) return 0; long long ans = 1; b %= m; while (e > 0){ if ((e & 1LL)) ans = (ans * b) % m; e = e >> 1LL; b = (b*b) % m; } return ans; } int main(){ long long W, H; string S; cin >> W >> H; UnionFind tree(W+10); while(H){ H--; cin >> S; bool f=1; vector> v(26); for (int j=0; j