// 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 pq 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 ll
#define discretize(x) sort(x.begin(), x.end()); x.erase(unique(x.begin(), x.end()), x.end());
//
// Subtask 1
const int INF = 1e9;
void solve() {
int n, m;
cin >> n >> m;
vector<int> a(n+1), suff(n+1);
int mx = 0, ind = 0;
for(int i=1; i<=n; ++i) {
cin >> a[i];
if(a[i] >= mx) {
mx = a[i];
ind = i;
}
}
for(int i=0; i<m; ++i) {
int u, v;
cin >> u >> v;
}
int ans = 0, h = 0;
for(int i=1; i<ind; ++i) {
ans += max(1ll, (a[i+1] - h));
h = max(h, a[i+1]);
if(a[i+1] <= a[i])
h++;
}
ans += max(mx, n-ind);
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;
}
/* CHECK :
1. COMPARATOR FUNCTION MUST RETURN FALSE WHEN ARGUMENTS ARE EQUAL!!!
2. Overflow! Typecase int64_t on operations if varaibles are int
3. Check array bounds!!!
4. Check array indexing!!!
5. Edge cases. (N==1)!!!
*/
