#include <bits/stdc++.h>
#define _FOR(i, a, b) for (int (i) = (a); (i) <= (b); ++(i))
#define _FRO(i, a, b) for (int (i) = (a); (i) < (b); ++(i))
#define _ROF(i, a, b) for (int (i) = (a); (i) >= (b); --(i))
#define _ORF(i, a, b) for (int (i) = (a); (i) < (b); --(i))
using namespace std;
typedef long long ll;
typedef double db;

const int maxn = 1e4 + 5;
const int maxm = 1e5 + 5;

struct Edge{
    int u, v, nxt;
}e[maxm], ed[maxm];

int cnt, head[maxn], d[maxn], tot, n, m, t, sd[maxn], p[maxn];
int dis[maxn], ans, head2[maxn], low[maxn], dfn[maxn];
int s[maxn], top;
bool vis[maxn];

queue<int> q;
// stack<int> s;

void add(int u, int v){
    e[++cnt].v = v;
    e[cnt].u = u;
    e[cnt].nxt = head[u];
    head[u] = cnt;
    return ;
}

void tarjian(int x){
    low[x] = dfn[x] = ++t;
    // s.push(x);
    s[++top] = x;
    vis[x] = 1;
    for (int i = head[x]; i; i = e[i].nxt){
        int v = e[i].v;
        if (!dfn[v]){
            tarjian(v);
            low[x] = min(low[x], low[v]);
        }
        else if (vis[v]) low[x] = min(low[x], dfn[v]);
    }
    if (dfn[x] == low[x]){
        int y;
        while(y = s[top--]){
            sd[y] = x;
            vis[y] = 0;
            if (x == y) break;
            p[x] += p[y];
        }
    }
    return ;
}

void topo(){
    _FOR(i, 1, n){
        if (sd[i] == i && !d[i]){
            q.push(i);
            dis[i] = p[i];
        }
    }
    while(!q.empty()){
        int x = q.front();
        q.pop();
        for (int i = head2[x]; i; i = ed[i].nxt){
            int y = ed[i].v;
            dis[y] = max(dis[y], dis[x] + p[y]);
            d[y]--;
            if (!d[y]) q.push(y);
        }
    }
    _FOR(i, 1, n) ans = max(ans, dis[i]);
    return ;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m;
    _FOR(i, 1, n) cin >> p[i];
    _FOR(i, 1, m){
        int u, v;
        cin >> u >> v;
        add(u, v);
    }
    _FOR(i, 1, n){
        if (!dfn[i]) tarjian(i);
    }
    _FOR(i, 1, m){
        int x = sd[e[i].u], y = sd[e[i].v];
        if (x == y) continue;
        ed[++tot].v = y;
        e[tot].u = x;
        e[tot].nxt = head2[x];
        head2[x] = tot;
        d[y]++;
    }
    topo();
    cout << ans;
    return 0;
}