#line 1 "main.cpp" //#pragma GCC target("avx") //#pragma GCC optimize("O3") //#pragma GCC optimize("unroll-loops") #include #ifdef LOCAL #include #define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__) #else #define debug(...) (static_cast(0)) #endif using namespace std; using ll = long long; using ld = long double; using pll = pair; using pii = pair; using vi = vector; using vvi = vector; using vvvi = vector; using vl = vector; using vvl = vector; using vvvl = vector; using vpii = vector; using vpll = vector; using vs = vector; template using pq = priority_queue, greater>; #define overload4(_1, _2, _3, _4, name, ...) name #define overload3(a,b,c,name,...) name #define rep1(n) for (ll UNUSED_NUMBER = 0; UNUSED_NUMBER < (n); ++UNUSED_NUMBER) #define rep2(i, n) for (ll i = 0; i < (n); ++i) #define rep3(i, a, b) for (ll i = (a); i < (b); ++i) #define rep4(i, a, b, c) for (ll i = (a); i < (b); i += (c)) #define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__) #define rrep1(n) for(ll i = (n) - 1;i >= 0;i--) #define rrep2(i,n) for(ll i = (n) - 1;i >= 0;i--) #define rrep3(i,a,b) for(ll i = (b) - 1;i >= (a);i--) #define rrep4(i,a,b,c) for(ll i = (a) + ((b)-(a)-1) / (c) * (c);i >= (a);i -= c) #define rrep(...) overload4(__VA_ARGS__, rrep4, rrep3, rrep2, rrep1)(__VA_ARGS__) #define all1(i) begin(i) , end(i) #define all2(i,a) begin(i) , begin(i) + a #define all3(i,a,b) begin(i) + a , begin(i) + b #define all(...) overload3(__VA_ARGS__, all3, all2, all1)(__VA_ARGS__) #define sum(...) accumulate(all(__VA_ARGS__),0LL) template bool chmin(T &a, const T &b){ if(a > b){ a = b; return 1; } else return 0; } template bool chmax(T &a, const T &b){ if(a < b){ a = b; return 1; } else return 0; } template auto min(const T& a){ return *min_element(all(a)); } template auto max(const T& a){ return *max_element(all(a)); } template void in(Ts&... t); #define INT(...) int __VA_ARGS__; in(__VA_ARGS__) #define LL(...) ll __VA_ARGS__; in(__VA_ARGS__) #define STR(...) string __VA_ARGS__; in(__VA_ARGS__) #define CHR(...) char __VA_ARGS__; in(__VA_ARGS__) #define DBL(...) double __VA_ARGS__; in(__VA_ARGS__) #define LD(...) ld __VA_ARGS__; in(__VA_ARGS__) #define VEC(type, name, size) vector name(size); in(name) #define VV(type, name, h, w) vector> name(h, vector(w)); in(name) ll intpow(ll a, ll b){ ll ans = 1; while(b){if(b & 1) ans *= a; a *= a; b /= 2;} return ans;} ll modpow(ll a, ll b, ll p){ ll ans = 1; a %= p;if(a < 0) a += p;while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; } ll GCD(ll a,ll b) { if(a == 0 || b == 0) return 0; if(a % b == 0) return b; else return GCD(b,a%b);} ll LCM(ll a,ll b) { if(a == 0) return b; if(b == 0) return a;return a / GCD(a,b) * b;} namespace IO{ #define VOID(a) decltype(void(a)) struct setting{ setting(){cin.tie(nullptr); ios::sync_with_stdio(false);fixed(cout); cout.precision(12);}} setting; template struct P : P{}; template<> struct P<0>{}; template void i(T& t){ i(t, P<3>{}); } void i(vector::reference t, P<3>){ int a; i(a); t = a; } template auto i(T& t, P<2>) -> VOID(cin >> t){ cin >> t; } template auto i(T& t, P<1>) -> VOID(begin(t)){ for(auto&& x : t) i(x); } template void ituple(T& t, index_sequence){ in(get(t)...);} template auto i(T& t, P<0>) -> VOID(tuple_size{}){ ituple(t, make_index_sequence::value>{});} #undef VOID } #define unpack(a) (void)initializer_list{(a, 0)...} template void in(Ts&... t){ unpack(IO :: i(t)); } #undef unpack static const double PI = 3.1415926535897932; template struct REC { F f; REC(F &&f_) : f(forward(f_)) {} template auto operator()(Args &&...args) const { return f(*this, forward(args)...); }}; constexpr int mod = 1000000007; //constexpr int mod = 998244353; #line 1 "library/data-structure/unionfind.hpp" struct unionfind { public: unionfind() : _n(0) {} explicit unionfind(int n) : _n(n), parent_or_size(n, -1) {} int merge(int a, int b) { assert(0 <= a && a < _n); assert(0 <= b && b < _n); int x = find(a), y = find(b); if (x == y) return x; if (-parent_or_size[x] < -parent_or_size[y]) swap(x, y); parent_or_size[x] += parent_or_size[y]; parent_or_size[y] = x; return x; } bool same(int a, int b) { assert(0 <= a && a < _n); assert(0 <= b && b < _n); return find(a) == find(b); } int find(int a) { assert(0 <= a && a < _n); if (parent_or_size[a] < 0) return a; return parent_or_size[a] = find(parent_or_size[a]); } int size(int a) { assert(0 <= a && a < _n); return -parent_or_size[find(a)]; } vector> groups() { vector leader_buf(_n), group_size(_n); for (int i = 0; i < _n; i++) { leader_buf[i] = find(i); group_size[leader_buf[i]]++; } vector> result(_n); for (int i = 0; i < _n; i++) { result[i].reserve(group_size[i]); } for (int i = 0; i < _n; i++) { result[leader_buf[i]].push_back(i); } result.erase( remove_if(result.begin(), result.end(), [&](const vector& v) { return v.empty(); }), result.end()); return result; } private: int _n; // root node: -1 * component size // otherwise: parent vector parent_or_size; }; #line 87 "main.cpp" template void warshall_floyd(vector> &g) { int n = g.size(); for(int k = 0;k < n;k++) { for(int i = 0;i < n;i++) { for(int j = 0;j < n;j++) { if(g[i][j] > g[i][k] + g[k][j]) { g[i][j] = g[i][k] + g[k][j]; } } } } } #include using namespace atcoder; int main() { INT(n,m); vvi g(n); unionfind uf(n); vvi dist(n,vi(n,1e9)); rep(i,n) dist[i][i] = 0; rep(i,m) { INT(a,b); a--,b--; uf.merge(a,b); dist[a][b] = dist[b][a] = 1; g[a].emplace_back(b); g[b].emplace_back(a); } warshall_floyd(dist); VEC(int,c,n); auto gs = uf.groups(); int ans = 0; rep(i,gs.size()) { int cnt = 0; vi idx(gs[i].size()); rep(j,gs[i].size()) { if(c[gs[i][j]]) { idx[j] = cnt; cnt++; } } if(cnt % 2) { cout << -1 << '\n'; return 0; } mcf_graph mfg(2*cnt+2); int st = 2 * cnt,gl = 2 * cnt + 1; rep(j,gs[i].size()) { if(c[gs[i][j]]) { mfg.add_edge(st,idx[j],1,0); mfg.add_edge(idx[j] + cnt,gl,1,0); rep(k,j+1,gs[i].size()) { if(c[gs[i][k]]) { mfg.add_edge(idx[j],idx[k] + cnt,1,dist[gs[i][j]][gs[i][k]]); mfg.add_edge(idx[k],idx[j] + cnt,1,dist[gs[i][j]][gs[i][k]]); } } } } ans += mfg.flow(st,gl).second / 2; } cout << ans << '\n'; }