#include<bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

#define F first
#define S second

const int MAXN = 1e5 + 10;

int n, m, a[MAXN], b[MAXN], sec[MAXN];
vector<int> adj[MAXN];
int par[MAXN];
ll ans[MAXN], sumB[MAXN];
pair<ll, ll> gec[MAXN];

bool cmp(int u, int v){return a[u]-b[u] < a[v]-b[v];}

int getPar(int v){return par[v]==v? v: par[v]=getPar(par[v]);}

bool mark[MAXN];
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin >> n >> m;
	for (int i = 0; i < n; i++) cin >> a[i] >> b[i], a[i] = max(a[i], b[i]);
	while (m--){
		int u, v; cin >> u >> v, u--, v--;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	iota(sec, sec + n, 0);
	sort(sec, sec + n, cmp);

	iota(par, par + n, 0);
	for (int i = 0; i < n; i++){
		int v = sec[i];
		mark[v] = true;
		sumB[v] = b[v];

		int tt = 0;
		for (int u:adj[v]){
			if (!mark[u]) continue;
			int pu = getPar(u);
			if (pu == v) continue;

			gec[tt++] = {ans[pu], sumB[pu]};
			par[pu] = v;
			sumB[v] += sumB[pu];
		}

		ans[v] = sumB[v] + (a[v] - b[v]);
		for (int j = 0; j < tt; j++){
			auto x = gec[j];
			ans[v] = min(ans[v], max((ll)a[v], x.F+b[v]) + (sumB[v] - b[v] - x.S));
		}
	}

	cout << ans[sec[n-1]] << "\n";
	return 0;
}
