#include <bits/stdc++.h>
using namespace std;
#define print(l) for(auto i:l) cout<<i<<" ";cout<<endl;
#define input(t,l,n) vector<t>l(n);for(int i = 0;i<n;i++)cin>>l[i];
#define int long long
#define pb push_back
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define all(l) l.begin(),l.end()
#define pii pair<int,int>
#define fi first
#define se second
const int M = 1e9+7;
const int inf = 1e18;
void io(){
#ifndef ONLINE_JUDGE
freopen("input.in","r",stdin);
// freopen("outputf.in","w",stdout);
#endif
ios::sync_with_stdio(0);//DO NOT USE IN INTERACTIVE
cin.tie(0), cout.tie(0);
cout << fixed<<setprecision(9);
}
int bp(int x, int y, int p){
int res = 1;
x = x % p;
while (y > 0) {
if (y & 1)
res = (res * x) % p;
y = y >> 1;
x = (x * x) % p;
}
return res;
}
int MI(int n, int p){
return bp(n, p - 2, p);
}
int mul(int x,int y, int p){
return x * 1ull * y % p;
}
int di(int x,int y, int p){
return mul(x, MI(y, p), p);
}
vector<vector<vector<int>>>adj;
vector<int>co;
int ans = inf;
int n , m , k , q;
void yn(int t){
if(t){
cout<<"YES"<<endl;
}
else{
cout<<"NO"<<endl;
}
}
void dfs(int u,int al,int canin,int inde){
// if(u == n){
// return;
// }
for(auto x:adj[u]){
// if(u == 1){print(x);}
int ral = x[1];
int v = x[0];
// if(u == 1)cout<<al<<" "<<ral<<" "<<u<<" "<<v<<endl;
int acos = 0;
int ncanin = canin;
int ninde = inde;
if(ral > al){
int delta = ral-al-1;
int x = min(delta,ncanin);
delta-=x;
ncanin-=x;
x = min(delta,ninde);
delta-=x;
ninde-=x;
acos+=delta;
if(co[v] >= co[u]+acos+1){
co[v] = co[u]+acos+1;
if(v == n){
ans = min(ans,co[v]+max(0ll,al-ninde));
return;
}
dfs(v,ral,ncanin+ninde,0);
}
}
else if(ral == al){
ncanin++;
if(co[v] >= co[u]+acos+1){
co[v] = co[u]+acos+1;
if(v == n){
ans = min(ans,co[v]);
return;
}
dfs(v,ral,ncanin+ninde,0);
}
}
else{
ninde++;
int x = ninde-min(ninde,al-ral);
ninde = min(ninde,al-ral);
if(co[v] >= co[u]+acos+1){
co[v] = co[u]+acos+1;
if(v == n){
// cout<<co[v]<<" "<<al<<" "<<ninde<<endl;
ans = min(ans,co[v]+max(0ll,al-ninde));
return;
}
dfs(v,al,ncanin+x,ninde);
}
}
}
}
void solve(int testcase_number){
cin>>n>>m;
adj.resize(n+1);
co.resize(n+1,1e18);
co[1] = 0;
input(int,l,n);
for(int i =0 ;i<m;i++){
int u,v;
cin>>u>>v;
if(u<v)adj[u].pb({v,l[v-1]});
else adj[v].pb({u,l[u-1]});
}
dfs(1,0,0,0);
cout<<ans<<endl;
}
signed main(){
// io();
int t = 1;
// cin>>t;
for(int i = 1;i<=t;i++){
solve(i);
}
}
