#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
#define pb push_back
#define all(x) begin(x), end(x)
#define rsz resize
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define R0F(i, a) for (int i = (a) - 1; i >= 0; i--)
#define ROF(i, a, b) for (int i = (b); i >= a; i--)
#define trav(a, x) for (auto &a : x)
/* SCC from BenQ */
struct SCC {
int N;
vector<vi> adj, radj;
vi todo, comps, comp;
vector<bool> vis;
void init(int _N) {
N = _N;
adj.rsz(N), radj.rsz(N), comp = vi(N, -1), vis.rsz(N);
}
void ae(int x, int y) { adj[x].pb(y), radj[y].pb(x); }
void dfs(int x) {
vis[x] = 1;
trav(y, adj[x]) if (!vis[y]) dfs(y);
todo.pb(x);
}
void dfs2(int x, int v) {
comp[x] = v;
trav(y, radj[x]) if (comp[y] == -1) dfs2(y, v);
}
void gen(int _N) { // fills allComp
FOR(i, 1, _N) if (!vis[i]) dfs(i);
reverse(all(todo));
trav(x, todo) if (comp[x] == -1) {
dfs2(x, x);
comps.pb(x);
}
}
};
const int maxn = 1e5 + 5;
int n, m;
SCC scc; // scc
int value[maxn]; // value of each room
ll group[maxn]; // value in each SCC
vi rgraph[maxn]; // reverse graph
ll dp[maxn];
// calculates dp[i]
ll DP(int i) {
if (dp[i]) return dp[i];
// start at i
dp[i] = group[i];
// simulate traveling from another SCC to this SCC
trav(j, rgraph[i]) dp[i] = max(dp[i], DP(j) + group[i]);
return dp[i];
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m;
scc.init(n + 1);
FOR(i, 1, n) cin >> value[i];
while (m--) {
int a, b;
cin >> a >> b;
scc.ae(a, b);
}
// generate SCC
scc.gen(n);
// set dp to 0
fill(dp + 1, dp + n + 1, 0);
// precompute group value for each SCC
FOR(i, 1, n) group[scc.comp[i]] += value[i];
// create reverse edges for SCC
FOR(i, 1, n) trav(j, scc.adj[i]) {
if (scc.comp[i] == scc.comp[j]) continue;
rgraph[scc.comp[j]].pb(scc.comp[i]);
}
// find dp value for each SCC
ll ans = 0;
trav(i, scc.comps) ans = max(ans, DP(i));
cout << ans << '\n';
}
