#include using namespace std; using int128 = __int128_t; using int64 = long long; using int32 = int; using uint128 = __uint128_t; using uint64 = unsigned long long; using uint32 = unsigned int; #define ALL(obj) (obj).begin(),(obj).end() template using priority_queue_reverse = priority_queue,greater>; constexpr int64 MOD = 1'000'000'000LL + 7; //' constexpr int64 MOD2 = 998244353; constexpr int64 HIGHINF = 1'000'000'000'000'000'000LL; constexpr int64 LOWINF = 1'000'000'000'000'000LL; //' constexpr long double PI = 3.1415926535897932384626433L; template vector multivector(size_t N,T init){return vector(N,init);} template auto multivector(size_t N,T... t){return vector(N,multivector(t...));} template void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}} template ostream &operator<<(ostream &o, const map&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;} template ostream &operator<<(ostream &o, const set&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;} template ostream &operator<<(ostream &o, const multiset&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;} template ostream &operator<<(ostream &o, const vector&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;} template ostream &operator<<(ostream &o, const deque&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;} template ostream &operator<<(ostream &o, const pair&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;} void print(void) {cout << endl;} template void print(Head&& head) {cout << head;print();} template void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward(tail)...);} template void chmax(T& a, const T b){a=max(a,b);} template void chmin(T& a, const T b){a=min(a,b);} vector split(const string &str, const char delemiter) {vector res;stringstream ss(str);string buffer; while( getline(ss, buffer, delemiter) ) res.push_back(buffer); return res;} inline constexpr int msb(int x) {return x?31-__builtin_clz(x):-1;} inline constexpr int64 ceil_div(const int64 a,const int64 b) {return (a+(b-1))/b;}// return ceil(a/b) void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;} void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;} void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;} /** * @url * @est */ int main() { cin.tie(0);ios::sync_with_stdio(false); int N,M; cin >> N >> M; vector> edges(N+1+M); vector C(M); for(int i=0;i> K; cin >> C[i]; for(int j=0;j> s; edges[s].push_back(i+N+1); edges[i+N+1].push_back(s); } } priority_queue_reverse,int>> pq; vector dp(N+1+M,HIGHINF); dp[1] = 0; pq.push({{0,0},1}); while(pq.size()) { auto p = pq.top(); pq.pop(); int64 cost = p.first.first; int pre = p.first.second; int from = p.second; if(dp[from] < cost) continue; if(N+1<=from) { for(int to:edges[from]) { if(dp[to] > dp[from] + (to+pre+1)/2) { dp[to] = dp[from] + (to+pre+1)/2; pq.push({{dp[to],0},to}); } } } else { for(int to:edges[from]) { if(dp[to] > dp[from] + C[to-(N+1)]) { dp[to] = dp[from] + C[to-(N+1)]; pq.push({{dp[to],from},to}); } } } } int64 ans = dp[N]; if(ans >= HIGHINF) ans = -1; cout << ans << endl; return 0; }