#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>
typedef long long ll;
typedef long double ld;
using namespace std;
const int N = 1e5 + 5;
int n, m;
int par[N];
vector<array<int, 3>> v;
int find(int u) {
	return par[u] == u ? u : par[u] = find(par[u]);
}
int main() {
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    cin >> n >> m;
    for(int i = 0;i < m;i++) {
		int c, a;
		cin >> c >> a;
		v.push_back({a, 0, c});
	}
	for(int i = 1;i <= n;i++) {
		par[i] = i;
		int b;
		cin >> b;
		v.push_back({b,i,(i+1)%n + 1});
	}
	sort(v.begin(), v.end());
	ll ans = 0;
	for(auto i : v) {
		int c = i[0];
		int a = i[1];
		int b = i[2];
		if(find(a) != find(b)) {
			ans += c;
			par[find(a)] = find(b);
		}
	}
	cout << ans;
    return 0;
}