#include <bits/stdc++.h>
using namespace std;
struct InputReader {
  char buf[1000001];
  int p;
  inline InputReader() { p = 1000001; }
  inline void Flush() {
    p = 0;
    fread(buf, 1, 1000001, stdin);
  }
  inline char C() {
    if (p >= 1000001) Flush();
    return buf[p++];
  }
  inline char Readnum() {
    char ch = C();
    while (!isdigit(ch) && ch != '-') ch = C();
    return ch;
  }
  inline void Readalpha(char &c) {
    c = C();
    while (!isalpha(c)) c = C();
  }
  int operator()() {
    int ans = 0, fu = 1;
    char ch = Readnum();
    if (ch == '-') fu = -1, ch = C();
    while (ch >= '0' && ch <= '9') {
      ans = ans * 10 + ch - '0';
      ch = C();
    }
    return ans * fu;
  }
  long long Readll() {
    long long ans = 0LL, fu = 1LL;
    char ch = Readnum();
    if (ch == '-') fu = -1LL, ch = C();
    while (ch >= '0' && ch <= '9') {
      ans = ans * 10LL + ch - '0';
      ch = C();
    }
    return ans * fu;
  }
  inline void Readstring(string &x) {
    x.clear();
    char ch = C();
    while (!isdigit(ch) && !isalpha(ch) && ch != '#' && ch != '.') ch = C();
    while (isdigit(ch) || isalpha(ch) || ch == '#' || ch == '.') {
      x += ch;
      ch = C();
    }
  }
  inline void Readchstring(char s[]) {
    int len = 0;
    char ch = C();
    while (!isdigit(ch) && !isalpha(ch)) ch = C();
    while (isdigit(ch) || isalpha(ch)) {
      s[len++] = ch;
      ch = C();
    }
    s[len] = '\0';
  }
  inline void Specialread(char &c) {
    c = C();
    while (!isdigit(c) && !isalpha(c) && c != '#' && c != '.' && c != '=' &&
           c != 'B')
      c = C();
  }
} In;
inline void Read(int &x) { x = In(); }
inline void Read(int &x, int &y) {
  x = In();
  y = In();
}
inline void Read(int &x1, int &x2, int &x3) {
  x1 = In();
  x2 = In();
  x3 = In();
}
inline void Read(int &x1, int &x2, int &x3, int &x4) {
  x1 = In();
  x2 = In();
  x3 = In();
  x4 = In();
}
inline void Read(long long &x) { x = In.Readll(); }
inline void Read(long long &x, long long &y) {
  x = In.Readll();
  y = In.Readll();
}
inline void Read(long long &x1, long long &x2, long long &x3) {
  x1 = In.Readll();
  x2 = In.Readll();
  x3 = In.Readll();
}
inline void Read(long long &x1, long long &x2, long long &x3, long long &x4) {
  x1 = In.Readll();
  x2 = In.Readll();
  x3 = In.Readll();
  x4 = In.Readll();
}
template <typename T>
void Read(T a[], int st, int ed) {
  for (int(i) = (st); (i) <= (ed); ++(i)) Read(a[i]);
}
inline void FILEIO() {}
inline void FILEIO(string pname) {
  freopen((pname + ".in").c_str(), "r", stdin);
  freopen((pname + ".out").c_str(), "w", stdout);
}
inline void FILEIO_OICONTEST(string pname) {
  freopen((pname + ".in").c_str(), "r", stdin);
  freopen((pname + ".out").c_str(), "w", stdout);
}
void Printtime() {}
void END() {
  Printtime();
  exit(0);
}
template <typename T>
void END(T mes) {
  cout << mes << endl;
  END();
}
template <typename T>
void Print(T a[], int s, int t, char sp = ' ', char ed = '\n') {
  if (s > t) return;
  for (int i = s; i < t; i++) cout << a[i] << sp;
  cout << a[t] << ed;
  cout.flush();
}
template <typename T>
void Print(T a, int s = 0, int t = -1, char sp = ' ', char ed = '\n') {
  if (t == -1) t = a.size() - 1;
  for (int i = s; i <= t; i++) cout << a[i] << sp;
  cout << ed;
  cout.flush();
}
long long Pow(long long a, long long b, long long p = (998244353LL)) {
  long long ret = 1;
  for (; b; a = a * a % p, b >>= 1LL)
    if (b & 1LL) ret = ret * a % p;
  return ret;
}
long long Inv(long long a, long long p = (998244353LL)) {
  return Pow(a, p - 2LL, p);
}
long long Frac(long long x) {
  long long ret = 1;
  for (int(i) = 1; (i) <= (x); ++(i)) ret = ret * i % (998244353LL);
  return ret;
}
int n, m;
int need[262144];
vector<pair<int, int> > off;
vector<int> canoff[262144];
bool Check(int lim) {
  static int tneed[262144];
  for (int(i) = 1; (i) <= (n); ++(i)) tneed[i] = need[i];
  int money = lim, costed = 0;
  for (int(i) = (((lim) < (200001) ? (lim) : (200001))); (i) >= 1; --(i)) {
    (money) = (((money)) < ((i)) ? ((money)) : ((i)));
    for (auto tp : canoff[i]) {
      while (1) {
        if (!tneed[tp]) break;
        if (!money) break;
        --money;
        ++costed;
        --tneed[tp];
      }
    }
  }
  int still = accumulate(tneed + 1, tneed + 1 + n, 0);
  return still * 2 <= lim - costed;
}
int Binarysearch() {
  int l = 1, r = 600000, mid, ans = (0x3f3f3f3f);
  while (l <= r) {
    mid = l + r >> 1;
    if (Check(mid)) {
      ans = mid;
      r = mid - 1;
    } else {
      l = mid + 1;
    }
  }
  assert(ans != (0x3f3f3f3f));
  return ans;
}
int main() {
  FILEIO();
  Read(n, m);
  for (int(i) = 1; (i) <= (n); ++(i)) Read(need[i]);
  for (int(i) = 1; (i) <= (m); ++(i)) {
    int a;
    Read(a);
    ;
    int b;
    Read(b);
    ;
    ;
    off.push_back({a, b});
    canoff[a].push_back(b);
  }
  sort(off.begin(), off.end());
  int ans = Binarysearch();
  cout << ans << endl;
  END();
}
