//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("Ofast")

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

#define pb push_back
#define pii pair<int, int>
#define mp make_pair
#define loop(i, n) for(int i = 0; i < (int)n; ++i)
#define loop1(i, n) for(int i = 1; i <= (int)n; ++i)
#define F first
#define S second
#define sorted(a) sort(a.begin(), a.end())

vector <ll> a;
vector <ll> tree;

void build(int v, int l, int r) {
    if (l == r) {
        tree[v] = a[l];
    }
    else {
        int mid = (l + r) / 2;
        build(2 * v, l, mid);
        build(2 * v + 1, mid + 1, r);
        tree[v] = tree[2 * v] + tree[2 * v + 1];
    }
}

ll sum(int v, int l, int r, int tl, int tr) {
    if (l == tl && r == tr) {
        return tree[v];
    }
    else if (l > r) {
        return 0;
    }
    else {
        int mid = (tl + tr) / 2;
        return sum(2 * v, l, min(r, mid), tl, mid) + sum(2 * v + 1, max(mid + 1, l), r, mid + 1, tr);
    }
}

ll suf(int v, int tl, int tr) {
    if (tl == tr) {
        return a[tl];
    }
    else {
        int mid = (tl + tr) / 2;
        return max(tree[2 * v + 1] + suf(2 * v, tl, mid), suf(2 * v + 1, mid + 1, tr));
    }
}

ll pref(int v, int tl, int tr) {
    if (tl == tr) {
        return a[tl];
    }
    else {
        int mid = (tl + tr) / 2;
        return max(tree[2 * v] + pref(2 * v + 1, mid + 1, tr), pref(2 * v, tl, mid));
    }
}

ll get_ans(int v, int tl, int tr) {
    int mid = (tl + tr) / 2;
    return max(suf(2 * v, tl, mid) + pref(2 * v + 1, mid + 1, tr), max(get_ans(2 * v, tl, mid), get_ans(2 * v + 1, mid + 1, tr)));
}

void update(int v, int i, ll x, int tl, int tr) {
    if (tl == tr) {
        tree[v] = x;
    }
    else {
        int mid = (tl + tr) / 2;
        if (i <= mid) {
            update(2 * v, i, x, tl, mid);
        }
        else {
            update(2 * v, i, x, mid + 1, tr);
        }
        tree[v] = tree[2 * v] + tree[2 * v + 1];
    }
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int n, m;
    cin >> n >> m;
    a.resize(n); tree.resize(4 * n);
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
    }
    for (int i = 0; i < m; ++i) {
        int j; ll x;
        cin >> j >> x;
        update(1, j, x, 0, n - 1);
        cout << get_ans(1, 0, n - 1) << "\n";
    }
    return 0;
}