#include<bits/stdc++.h>
using namespace std;
#define foru(i,a,b) for(int i=(a); i<=(b); ++i)
#define ford(i,a,b) for(int i=(a); i>=(b); --i)
#define rep(i,a) for(int i=0; i<(a); ++i)
#define sz(a) (int)(a).size()
#define all(a) (a).begin(),(a).end()
#define bit(s,i) (((s)>>(i))&1)
#define ii pair<int,int>
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define ll long long
#define _ << " " <<
template <class X, class Y> bool maxi(X &x, Y y){return x<y?x=y,true:false;}
template <class X, class Y> bool mini(X &x, Y y){return x>y?x=y,true:false;}
const int N=2e5+5;
int n,q,c[N]; ll tot;
void init(){
cin>>n>>q;
foru(i,1,n) cin>>c[i], tot+=c[i];
}
struct Node{
ll open,close,num;
Node(){
open=close=num=0;
}
} st[N<<3];
Node combine(Node a, Node b){
Node tmp;
ll t=min(a.open,b.close);
tmp.num=a.num+b.num+t;
tmp.open=a.open-t+b.open;
tmp.close=a.close+b.close-t;
return tmp;
}
void upd(int x, ii val){
int id=1, l=1, r=2*n-1;
while(true){
if(l==r) break;
int mid=(l+r)>>1;
if(x<=mid){
r=mid;
id=id<<1;
} else{
l=mid+1;
id=id<<1|1;
}
}
int &t=st[id].num;
st[id].open+=val.fi+t;
st[id].close+=val.se+t;
t=min(st[id].open, st[id].close);
st[id].open-=t;
st[id].close-=t;
while(id>1){
id/=2;
st[id]=combine(st[id<<1], st[id<<1|1]);
}
}
void buildSegtree(){
foru(i,1,n){
int open=c[i]&1, close=c[i]/2;
upd(i,{open,0});
upd(2*i-1,{0,close});
}
}
void answerQueries(){
foru(_q,1,q){
int l,d; cin>>l>>d;
int lstOpen=c[l]&1, lstClose=c[l]/2;
c[l]+=d; tot+=d;
int open=c[l]&1, close=c[l]/2;
upd(l,{open-lstOpen,0});
upd(2*l-1,{0,close-lstClose});
cout<<st[1].num + (tot-st[1].open-st[1].num*3)/3<<'\n';
}
}
void process(){
init();
buildSegtree();
answerQueries();
}
int main(){
#ifdef doramii
freopen("test.inp","r",stdin);
freopen("test.out","w",stdout);
#endif // doramii
cin.tie(0)->sync_with_stdio(0);
process();
}
