#include <bits/stdc++.h>

using namespace std;

#define int long long
#define ll long long
#define flt double
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()

mt19937 rnd(234);
const ll inf = 1e18;

int n, q;
vector<ll> c;
vector<pair<int, ll>> chngs;
vector<ll> rs;

void solve_slow() {
    rs.resize(q);
    vector<ll> a = c;
    for (int i = 0; i < q; i += 1) {
        auto [pos, d] = chngs[i];
        a[pos] += d;
        ll cnt = 0;
        auto b = a;
        deque<int> q;
        int pos_bebra = n;
        for (int j = n; j >= 1; j -= 1) {
            while (pos_bebra > 0 && (b[pos_bebra] % 2 == 0 || j * 2 < pos_bebra)) {
                pos_bebra -= 1;
            }
            while (b[j] >= 2 && pos_bebra > 0) {
                b[pos_bebra] -= 1;
                cnt += 1;
                b[j] -= 2;
                while (pos_bebra >= 0 && b[pos_bebra] % 2 == 0) {
                    pos_bebra -= 1;
                }
            }
        }
        ll aboba = 0;
        for (int j = n; j >= 1; j -= 1) {
            aboba += b[j] / 2;
        }
        cnt += (2 * aboba) / 3;
        rs[i] = cnt;
    }
}

int32_t main() {
    if (1) {
        ios::sync_with_stdio(0);
        cin.tie(0);
        cout.tie(0);
    }
    cin >> n >> q;
    c.resize(n + 1);
    for (int i = 1; i <= n; i += 1) {
        cin >> c[i];
    }
    chngs.resize(q);
    for (int i = 0; i < q; i += 1) {
        int pos;
        ll d;
        cin >> pos >> d;
        chngs[i] = make_pair(pos, d);
    }
    solve_slow();
    for (int i = 0; i < q; i += 1) {
        cout << rs[i] << "\n";
    }
    return 0;
}