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

using ll = long long;

template <class T>
struct FenwickTree { // queries are right-exclusive; 0-based
	int n;
	vector<T> tree;
	FenwickTree(int n) : n(n) { tree.assign(n + 1, 0); }
	T query(int l, int r) const { return query(r) - query(l); } // [l,r)
	T query(int r) const {                                      // [0,r)
		T s = 0;
		for(; r > 0; r -= (r & (-r))) s += tree[r];
		return s;
	}
	void update(int i, T v) {
		for(++i; i <= n; i += (i & (-i))) tree[i] += v;
	}
};

ll test(int i, ll s, const FenwickTree<ll> &ft, const vector<ll> &a) {
	ll pre = ft.query(i);
	ll suf = s - a[i] - pre;
	if (a[i]&1) (pre <= suf ? pre : suf)++;
	return pre - suf;
}

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

	int n, q;
	cin >> n >> q;
	vector<ll> a(n);
	FenwickTree<ll> ft(n + 1);
	for (int i = 0; i < n; ++i) {
		ll v;
		cin >> v;
		ft.update(i, a[i] = v);
	}

	while (q--) {
		int i;
		ll x;
		cin >> i >> x;
		ft.update(i, x - a[i]);
		a[i] = x;

		ll s = ft.query(0, n);
		int l = 0, r = n;
		while (l < r) {
			int m = (l + r) / 2;
			if (test(m, s, ft, a) < 0)
				l = m + 1;
			else
				r = m;
		}

		if (l > 0 && -test(l-1, s, ft, a) <= test(l, s, ft, a))
			--l;
		cout << l << '\n';
	}
	cout << flush;

	return 0;
}