#if !__INCLUDE_LEVEL__ #include __FILE__ int main() { int N,M;cin >> N >> M; vl H(N);rep(i,N)cin >> H[i]; vvl Root(N); rep(m,M){ int X,Y;cin >> X >> Y; X-=1; Y-=1; Root[Y].emplace_back(X); } vvl DP(N+1,vl(2,-INF)); DP[0][0]=0; DP[0][1]=0; rep(j,N){ fore(i,Root[j]){ if(H[i]H[j]){//登る場合 chmax(DP1[i][1],DP1[j][0]+H[i]-H[j]); } else{//下る場合 chmax(DP1[i][0],DP1[j][0]); chmax(DP1[i][0],DP1[j][1]); } } } ll ans2 = max(DP1[0][0],DP1[0][1]); if(ans2<0)cout << -1 << "\n"; else cout << ans2 << "\n"; } #else //tie(a, b, c) = t #include #include using namespace std; using namespace atcoder; #define rep(i, n) for(int i = 0; i < n; i++) #define rrep(i, n) for(int i = n-1; i >= 0; i--) #define range(i, m, n) for(int i = m; i < n; i++) #define fore(i,a) for(auto &i:a) #define all(v) v.begin(), v.end() #define rall(v) v.rbegin(), v.rend() #define Sum(v) accumulate(all(v),0LL) #define minv(v) *min_element(all(v)) #define maxv(v) *max_element(all(v)) typedef long long ll; typedef vector vl; typedef vector> vvl; const ll INF = 1e16; const ll MOD1 = 1000000007; const ll MOD2 = 998244353; template inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; } template inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; } ll SN(char s){return ll(s-'0');} ll SN(string s){return stoll(s);} int alpN(char s){return int(s-'a');} int AlpN(char s){return int(s-'A');} int Nalp(int n){return char(n+97);} int NAlp(int n){return char(n+65);} using Graph = vector>; using GraphCost = vector>>; using mint = modint; using mint1 = modint1000000007; using mint2 = modint998244353; using pll = pair; template ostream &operator<<(ostream &o,const vector&v){for(int i=0;i<(int)v.size();i++)o<<(i>0?" ":"")< bool contain(const std::string& s, const T& v) { return s.find(v) != std::string::npos; } ll max(int x,ll y){return max((ll)x,y);} ll max(ll x,int y){return max(x,(ll)y);} ll min(int x,ll y){return min((ll)x,y);} ll min(ll x,int y){return min(x,(ll)y);} template struct edge { int src, to; T cost; edge(int to, T cost) : src(-1), to(to), cost(cost) {} edge(int src, int to, T cost) : src(src), to(to), cost(cost) {} edge& operator=(const int& x) { to = x; return *this; } operator int() const { return to; } }; template using Edges = vector >; template using WeightedGraph = vector >; using UnWeightedGraph = vector >; template using Matrix = vector >; //unorderd_mapの拡張…https://qiita.com/hamamu/items/4d081751b69aa3bb3557 template size_t HashCombine(const size_t seed,const T &v){ return seed^(std::hash()(v)+0x9e3779b9+(seed<<6)+(seed>>2)); } /* pair用 */ template struct std::hash>{ size_t operator()(const std::pair &keyval) const noexcept { return HashCombine(std::hash()(keyval.first), keyval.second); } }; /* vector用 */ template struct std::hash>{ size_t operator()(const std::vector &keyval) const noexcept { size_t s=0; for (auto&& v: keyval) s=HashCombine(s,v); return s; } }; /* tuple用 */ template struct HashTupleCore{ template size_t operator()(const Tuple &keyval) const noexcept{ size_t s=HashTupleCore()(keyval); return HashCombine(s,std::get(keyval)); } }; template <> struct HashTupleCore<0>{ template size_t operator()(const Tuple &keyval) const noexcept{ return 0; } }; template struct std::hash>{ size_t operator()(const tuple &keyval) const noexcept { return HashTupleCore>::value>()(keyval); } }; ll ceil(ll a, ll b){ return (a + b - 1) / b; } #endif