#include <bits/stdc++.h>

using namespace std;
using ll = long long;

struct SegmentTree {
    ll mx = 0, tag = 0;
    int lx = 0, rx = 0;
    SegmentTree *left = nullptr, *right = nullptr;

    void apply(ll t) {
        tag += t, mx += t;
    }

    void push() {
        left->apply(tag);
        right->apply(tag);
        tag = 0;
    }

    void pull() {
        mx = max(left->mx, right->mx);
    }

    SegmentTree(int l, int r) : lx(l), rx(r) {
        if (lx + 1 < r) {
            int mid = lx + rx >> 1;
            left = new SegmentTree(lx, mid);
            right = new SegmentTree(mid, rx);
        }
    }

    void rangeAdd(int l, int r, ll t) {
        if (lx >= r || l >= rx) {
            return;
        } else if (l <= lx && rx <= r) {
            return apply(t);
        }
        push();
        left->rangeAdd(l, r, t);
        right->rangeAdd(l, r, t);
        pull();
    }
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, q;
    cin >> n >> q;

    vector<int> c(n + 1);

    for (int i = 1; i <= n; ++i) {
        cin >> c[i];
    }

    ll S = 0, cnt = 0;
    auto *t = new SegmentTree(0, n + 1);

    auto ins = [&](int i) {
        S += c[i] / 2, cnt += c[i] % 2;
        t->rangeAdd(1, min(n, i * 2 + 1) + 1, -(c[i] / 2));
        t->rangeAdd(1, i + 1, c[i] % 2);
    };

    auto era = [&](int i) {
        S -= c[i] / 2, cnt -= c[i] % 2;
        t->rangeAdd(1, min(n, i * 2 + 1) + 1, (c[i] / 2));
        t->rangeAdd(1, i + 1, -(c[i] % 2));
    };

    auto query = [&]() {
        ll C = cnt - t->mx;
        return C + (S - C) * 2 / 3;
    };

    for (int i = 1; i <= n; ++i) {
        ins(i);
    }

    while (q--) {
        int i, d;
        cin >> i >> d;
        era(i);
        c[i] += d;
        ins(i);
        cout << query() << '\n';
    }


    return 0;
}