// // Created by yamunaku on 2020/11/13. // #include //#include using namespace std; //using namespace atcoder; #define rep(i, n) for(int i = 0; i < (n); i++) #define repl(i, l, r) for(int i = (l); i < (r); i++) #define per(i, n) for(int i = ((n)-1); i >= 0; i--) #define perl(i, l, r) for(int i = ((r)-1); i >= (l); i--) #define all(x) (x).begin(),(x).end() #define MOD9 998244353 #define MOD1 1000000007 #define IINF 1000000000 #define LINF 1000000000000000000 #define SP <<" "<< #define CYES cout<<"YES"<; using mti = vector>; using vl = vector; using mtl = vector>; using pi = pair; using pl = pair; template using heap = priority_queue, function>; int main() { //CFS; int n, m; cin >> n >> m; vl b(n); rep(i, n) { cin >> b[i]; if (i & 1) b[i] = -b[i]; // cout << b[i] << " "; } // cout << endl; vector>> v(n + 1); vi l(m), r(m); rep(i, m) { cin >> l[i] >> r[i]; v[l[i] - 1].push(r[i] - 1); } vl rui(n + 1, 0); rep(i, n) { if (i > 0) rui[i] += rui[i - 1]; ll k = b[i] - rui[i]; // cout << i SP k << endl; if (v[i].empty()) { if (k == 0) continue; CNO; return 0; } int rr = v[i].top() + 1; // cout << rr << endl; rui[i] += k; rui[rr] -= k; while (!v[i].empty()) { if (v[i].top() == rr - 1) v[i].pop(); else break; } if (v[i].size() < v[rr].size()) { while (!v[i].empty()) { v[rr].push(v[i].top()); v[i].pop(); } } else { while (!v[rr].empty()) { v[i].push(v[rr].top()); v[rr].pop(); } v[rr] = move(v[i]); } } CYES; return 0; }