#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define f first
// #define s second
#define pb(x) push_back(x)
#define int long long
const int MOD = 1e9+7;
const int inf = 1e9;
const int INF = 1e18+20;
const int LOG = 25;
void solve() {
int n, m;
cin>>n>>m;
vector<int> a(n);
for (int i=0; i<n; i++) {
cin>>a[i];
}
for (int i=0; i<m; i++){
int x, y;
cin>>x>>y;
}
cout<<2*(*max_element(a.begin(), a.end()))<<endl;
}
bool multi=false;
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int t=1;
if (multi) cin>>t;
while (t--) solve();
return 0;
}
