#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<string>
#include<stack>
#include<queue>
#include<deque>
#include<set>
#include<vector>
#include<map>
#include<cmath>
#include<functional>#define fst first
#define sc second
#define pb push_back
#define mem(a,b) memset(a,b,sizeof(a))
#define lson l,mid,root<<1
#define rson mid+1,r,root<<1|1
#define lc root<<1
#define rc root<<1|1
#define lowbit(x) ((x)&(-x)) using namespace std;typedef double db;
typedef long double ldb;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> PI;
typedef pair<ll,ll> PLL;const db eps = 1e-6;
const int mod = 1e9+7;
const int maxn = 1e6+100;
const int maxm = 1e6+100;
const int inf = 0x3f3f3f3f;int a[maxn];
int b[maxn];
vector<int>v[maxn];
int dp[maxn];
int n,m;
int c(int x, int mid){return a[x]>=mid?1:-1;
}
void dpp(int x, int va,int mid){//printf("%d %d %d\n",x,va,mid);if(va<=dp[x])return;dp[x] = max(dp[x],va);//if(x==n)return;for(int i = 0; i < (int)v[x].size(); i++){dpp(v[x][i], va+c(v[x][i],mid),mid);}return;
}
bool ck(int x){//x = b[x];for(int i = 1; i <= n; i++)dp[i]=-0x3f3f3f3f;dpp(1,c(1,x),x);if(dp[n]>=0)return true;return false;
}
int main(){scanf("%d %d",&n,&m);for(int i =1 ; i <= n; i++){scanf("%d", &a[i]);}for(int i = 1; i <= m; i++){int x, y;scanf("%d %d", &x, &y);v[x].pb(y);}//printf("%d",ck(5));int l = 0, r = 1e9;int ans=-1;while(l<=r){int mid = (r+l)>>1;//printf("%d %d %d\n",l,r,mid);if(ck(mid)){l = mid+1;ans=mid;}else r = mid-1;}printf("%d", ans);return 0;
}