#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int maxn = 2e5 + 5;

int c[maxn];
ll C[maxn], P[maxn];

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0); 
	
	int n, q;
	cin >> n >> q;
	if (n > 2000) return 0;
	for (int i = 1; i <= n; i++) cin >> c[i];
	while (q--)
	{
		int l, d;
		cin >> l >> d;
		c[l] += d;
		
		for (int i = 1; i <= n; i++) C[i] = C[i - 1] + c[i], P[i] = 1e18;
		P[1] = c[1] / 3;
		for (int i = 1; i < n; i++)
		{
			P[i + 1] = min(P[i + 1], P[i] + c[i + 1] / 2);
			P[min(n, 2 * i - 1)] = min(P[min(n, 2 * i - 1)], (C[min(n, 2 * i - 1)] - P[i]) / 2);
		}
		cout << P[n] << "\n";
	}
	return 0;
}