#include <bits/stdc++.h> using namespace std; using ll = long long; #define vi vector<long long> #define all(x) x.begin(), x.end() #define endl "\n" #define pr pair<ll, ll> #define ff first #define ss second void solution(); int main(){ ios::sync_with_stdio(false); cin.tie(nullptr); solution(); return 0; } #define arr array<ll, 4> const int N = 2e5+10; vi adj[N]; ll a[N]; void solution() { ll n, m; cin >> n >> m; for (int i = 1; i <= n; i++) cin >> a[i]; while (m--) { int u, v; cin >> u >> v; adj[u].push_back(v); adj[v].push_back(u); } vi ng(n+1, -1); stack<ll> hs; for (int i = n; i >= 1; i--) { while (hs.size() > 0 && a[hs.top()] < a[i]) hs.pop(); if (hs.size()) ng[i] = hs.top(); hs.push(i); } ll ans = 0; ll x = 0; for (int i = 1; i < n;) { if (ng[i] == -1) { x--; ans++; i++; } else { ll delta = a[ng[i]] - x; x += delta; ans += max(delta, ng[i]-i); i = ng[i]; } } cout << ans + x << endl; }