#include <bits/stdc++.h>
using namespace std;
#define int long long
constexpr int INF = LONG_LONG_MAX;
int32_t main(){
int n,m;cin>>n>>m;
vector<int> arr(n);
for (int i = 0; i < n; ++i)
{
cin>>arr[i];
}
vector<vector<int>> tree(n);
for (int i = 0; i < m; i++){
int u,v;cin>>u>>v;
tree[u-1].push_back(v-1);
tree[v-1].push_back(u-1);
}
vector<int> suff = arr;
for (int i = n-2; i >= 0; i--){
suff[i]=max(suff[i+1],suff[i]);
}
int crh = 0;
int ans = 0;
int maxind = 0;
for (int i = 0; i < n; ++i)
{
if (arr[i]>arr[maxind]) maxind=i;
}
for (int i = 0; i < maxind; i++){
ans++;
if (crh<arr[maxind]){
crh++;
if (crh<arr[i+1]){
ans+=arr[i+1]-crh;
crh=arr[i+1];
}
}
}
for (int i = maxind; i < n-1; i++){
if (crh>suff[i+1]) crh--;
ans++;
}
cout<<ans+crh<<endl;
}
