// Programmer: Shadow1
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
using str = string; // yay python!
#define i64 int64_t
#define show(x) cerr << (#x) << " = " << (x) << '\n';
#define output_vector(v) for(auto &x : v){cout << x << ' ';}cout << '\n';
#define output_pairvector(v) for(auto &x : v){cout << x.first << " " << x.second << '\n';}
#define read_vector(v) for(auto &x : v){cin >> x;}
#define vt vector
#define prq priority_queue
#define pb push_back
#define eb emplace_back
#define pii pair<int,int>
#define fir first
#define sec second
#define sz(x) ll(x.size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define int long long
#define discretize(x) sort(x.begin(), x.end()); x.erase(unique(x.begin(), x.end()), x.end());
//
//
void solve() {
int n, m;
cin >> n >> m;
vector<int> a(n+1), p(n+1);
for(int i=1; i<=n; ++i)
cin >> a[i];
for(int i=0; i<m; ++i) {
int u, v;
cin >> u >> v;
}
vector<bool> skip(n+1);
for(int i=1; i<=n; ++i)
p[i] = max(p[i-1], a[i]);
int mx = 0, ind = 0;
for(int i=n-1; i>=2; --i) {
if(p[i-1] > a[i] && mx > a[i]) skip[i] = true;
mx = max(mx, a[i]);
}
vector<pii> v;
for(int i=1; i<=n; ++i) {
if(!skip[i]) {
v.push_back({a[i], i});
if(a[i] >= mx) ind = i;
}
}
int ans = 0, k = 0, curr = 0;
for(int i=1; i<sz(v); ++i) {
if(v[i].sec > ind) {
k = i;
break;
}
int old = curr;
curr = max(curr + (v[i].sec - v[i-1].sec), v[i].fir);
ans += max(v[i].sec - v[i-1].sec, curr - old);
}
for(int i=k; i<sz(v); ++i) {
int old = curr;
curr = max(curr - (v[i].sec - v[i-1].sec), v[i].fir);
ans += max(v[i].sec - v[i-1].sec, old - curr);
}
ans += curr;
cout << ans << '\n';
}
// CHECK YOUR OVERFLOWS!!!!
signed main() {
// freopen("output.txt", "w", stdout);
// freopen("input.txt", "r", stdin);
ios::sync_with_stdio(false);
cin.tie(NULL);
int T = 1;
// cin >> T;
for(int tc = 1; tc <= T; ++tc) {
// cout << "Case #" << tc << ": ";
solve();
}
return 0;
}
