#pragma GCC optimize("Ofast")
//#pragma GCC target ("sse4")

#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<unordered_set>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
#include<array>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
constexpr ll mod = 1000000007;
const ll INF = mod * mod;
typedef pair<int, int>P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-12;
const ld pi = acosl(-1.0);

ll mod_pow(ll x, ll n, ll m = mod) {
	if (n < 0) {
		ll res = mod_pow(x, -n, m);
		return mod_pow(res, m - 2, m);
	}
	if (abs(x) >= m)x %= m;
	if (x < 0)x += m;
	ll res = 1;
	while (n) {
		if (n & 1)res = res * x % m;
		x = x * x % m; n >>= 1;
	}
	return res;
}
struct modint {
	ll n;
	modint() :n(0) { ; }
	modint(ll m) :n(m) {
		if (n >= mod)n %= mod;
		else if (n < 0)n = (n % mod + mod) % mod;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint& a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint& a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint& a, modint b) { a.n = ((ll)a.n * b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, ll n) {
	if (n == 0)return modint(1);
	modint res = (a * a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }
modint operator/=(modint& a, modint b) { a = a / b; return a; }
const int max_n = 1 << 17;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}
modint combP(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[a - b];
}

void solve() {
	int n, m; cin >> n >> m;
	vector<ll> a(n);
	rep(i, n)cin >> a[i];
	vector<vector<int>> G(n);
	rep(i, m) {
		int x, y; cin >> x >> y; x--; y--;
		G[x].push_back(y);
	}
	vector<ll> dp(n);
	rep(i, n)dp[i] = INF;
	ll ans = -INF;
	rep(i, n) {
		ans = max(ans, a[i] - dp[i]);
		dp[i] = min(dp[i], a[i]);
		for (int to : G[i])dp[to] = min(dp[to], dp[i]);
	}
	cout << ans << "\n";
}

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(15);
	//init_f();
	//init();
	//expr();
	//int t; cin >> t; rep(i, t)
	solve();
	return 0;
}
#include<bits/stdc++.h>

using namespace std;

#define int                  long long
#define mod                  1000000007
#define ps(x, y)             fixed << setprecision(y) << x
#define w(x)                 int x; cin >> x; while(x --)
#define mk(arr, n, type)     type *arr = new type[n];
#define gcd(x, y)            __gcd(x, y)
#define len(x)               int(x.size())
#define PI                   3.1415926535897932384626433832795
#define for0(i, n)           for (int i = 0; i < (int)(n); i ++) //0 based indexing
#define for1(i, n)           for (int i = 1; i <= (int)(n); i ++) // 1 based indexing
#define forc(i, l, r)        for (int i = (int)(l); i <= (int)(r); ++i) // l to r inclusive
#define forr0(i, n)          for (int i = (int)(n) - 1; i >= 0; --i) // reverse 0 based.
#define forr1(i, n)          for (int i = (int)(n); i >= 1; --i) // reverse 1 base
//short hand for usual tokens
#define pb                   push_back
#define fi                   first
#define se                   second
// to be used with algorithms that processes a container Eg: find(all(c),42)
#define all(x)               (x).begin(), (x).end() //Forward traversal
#define rall(x)              (x).rbegin, (x).rend() //reverse traversal
// shorthand for common types
typedef vector<int> vi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
//static_cast<new_type>(expression)
//swap(a,b)
//sort(a, a + n) sort(all(x))
void solve(){
    int n; cin >> n;
    vector<pair<int, int>> arr1;
    for0(i, n){
        int a, b;
        cin >> a >> b;
        arr1.pb({a, b});
    }
    bool l = false;
    for(int i = 0; i < n; i ++){
        for(int j = i + 1; j < n; j ++){
            for(int k = j + 1; k < n; k ++){
                int a = arr1[i].first, b = arr1[i].second;
                int c = arr1[j].first, d = arr1[j].second;
                int e = arr1[k].first, f = arr1[k].second;
                if((a * (d - f) + c * (f - b) + e * (b - d)) == 0){
                    cout << "Yes" ;
                    l = true;
                    break;
                }
            }
            if(l) break;
        }
        if(l) break;
    }
    if(!l) cout << "No";
}
signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    solve();
    return 0;
}
