#include <bits/stdc++.h>
using namespace std;
#define all(a) begin(a), end(a)
using ll = long long;

/*
    l no nagai hou ga 3 honme no jouken ga yurui
    l no nagai hou kara, kisuu de amatteiru bou wo hirotteiku
    kore de hiroenai bou ha zettai ni tukaenai
    nokori ha pair ni natteru kara, l no mijikai pair kara kuzusu
    mod 3 dake nokotte, hoka ha zenbu tukaeru
    zettai ni tukaenai bou no kazu wo kazoeru
    segtree ni noru?
    
    l=1, l<=1, l=2, l=3, l<=3, ...
    zougen ga atte, ruisekiwa sita toki no minimum ga kotae
*/
struct T {
    ll add = 0, min = 0;
};
T operator+(T a, T b) {
    return {a.add + b.add, min(b.min, b.add + a.min)};
}
#ifdef DEBUG
const ll MAX = 1 << 3;
#else
const ll MAX = 1 << 19;
#endif
T seg[MAX * 2];
void add(ll i, ll x) {
    i += MAX;
    seg[i].min = min(0LL, seg[i].add += x);
    while(i >>= 1) seg[i] = seg[i << 1] + seg[i << 1 | 1];
}
ll get() {
    return seg[1].min;
}
int main() {
    cin.tie(0)->sync_with_stdio(0);
    ll N, Q;
    cin >> N >> Q;
    vector<ll> C(N);
    for(ll& c : C) cin >> c;
    ll num_edge = 0;
    C.insert(C.begin(), 0);
    for(ll l = 1; l <= N; l++) {
        ll& c = C[l];
        add(l, -(c % 2));
        add(l * 2 - 1, c / 2);
        num_edge += c;
    }
    
    while(Q--) {
        ll l, d;
        cin >> l >> d;
        ll& c = C[l];
        add(l, c % 2 - (c + d) % 2);
        add(l * 2 - 1, (c + d) / 2 - (c / 2));
        num_edge += d;
        cout << (num_edge + get()) / 3 << '\n';
    }
}