#include <bits/stdc++.h>

using namespace std;

#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif

#define ll long long
#define ld long double
#define endl '\n'
#define st first
#define nd second
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define FOR(i,l,r) for(int i=(l);i<=(r);i++)
#define ROF(i,r,l) for(int i=(r);i>=(l);i--)
int inf=1000000007;
ll infl=1000000000000000007;
ll mod=1000000007;
ll mod1=998244353;

const int N=200007,pot=1<<18;

ll seg[2*pot+7];
ll lzy[2*pot+7];

void push(int v)
{
	seg[2*v]+=lzy[v];
	lzy[2*v]+=lzy[v];
	seg[2*v+1]+=lzy[v];
	lzy[2*v+1]+=lzy[v];
	lzy[v]=0;
}
void ins(int v,int a,int b,int l,int r,ll x)
{
	if(a<=l&&b>=r)
	{
		seg[v]+=x;
		lzy[v]+=x;
		return ;
	}
	if(r<a||l>b) return ;
	push(v);
	ins(2*v,a,b,l,(l+r)/2,x);
	ins(2*v+1,a,b,(l+r)/2+1,r,x);
	seg[v]=min(seg[2*v],seg[2*v+1]);
}

ll a[N];

signed main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n,q;
	cin>>n>>q;
	ll tot=0,ile=0;
	FOR(i,1,n) 
	{
		cin>>a[i];
		tot+=a[i]/2;
		ins(1,1,i,1,pot,a[i]/2);
		if(a[i]%2==1) 
		{
			ins(1,1,(i+2)/2,1,pot,-1);
			ile++;
		}
		debug(seg[1]);
	}
	while(q--)
	{
		int p,x;
		cin>>p>>x;
		tot-=a[p]/2;
		ins(1,1,p,1,pot,-(a[p]/2));
		if(a[p]%2==1)
		{
			ins(1,1,(p+2)/2,1,pot,1);
			ile--;
		}
		a[p]+=x;
		tot+=a[p]/2;
		ins(1,1,p,1,pot,a[p]/2);
		if(a[p]%2==1) 
		{
			ins(1,1,(p+2)/2,1,pot,-1);
			ile++;
		}
		ll match=ile+min(0LL,seg[1]);
		ll ans=match;
		ans+=2*(tot-match)/3;
		debug(tot,ile,match);
		cout<<ans<<endl;
	}
	
	
	
	return 0;
}