#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool uin(T& a, T b) {
  return a > b ? (a = b, true) : false;
}
template <class T>
inline bool uax(T& a, T b) {
  return a < b ? (a = b, true) : false;
}
const int nax = 2e5 + 10;
vector<int> offer[nax];
int K[nax];
int N, M;
bool can(int day) {
  vector<int> last(N, -1);
  for (int i = 0; i <= min(day, nax - 1); ++i) {
    for (int x : offer[i]) {
      last[x] = i;
    }
  }
  vector<int> need(K, K + N);
  vector<int> temp_offer[nax];
  for (int i = 0; i < N; ++i)
    if (last[i] != -1) temp_offer[last[i]].push_back(i);
  int money = 0;
  for (int d = 0; d <= day; ++d) {
    ++money;
    if (d > 2e5) continue;
    for (int x : temp_offer[d]) {
      if (money >= need[x]) {
        money -= need[x];
        need[x] = 0;
      } else {
        need[x] -= money;
        money = 0;
        break;
      }
    }
  }
  for (int i = 0; i < N; ++i)
    ;
  ;
  return money >= 2 * accumulate(need.begin(), need.end(), 0);
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> N >> M;
  for (int i = 0; i < N; ++i) cin >> K[i];
  for (int d, t, i = 0; i < M; ++i) {
    cin >> d >> t;
    --d, --t;
    offer[d].push_back(t);
  }
  for (int i = 0; i < 10; ++i)
    ;
  int l = 0, r = 4e5;
  while (l < r) {
    int m = (l + r) / 2;
    ;
    if (can(m))
      r = m;
    else
      l = m + 1;
  }
  cout << r + 1 << '\n';
}
