bool M1;
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#include<climits>
#include<iomanip>
#include<cassert>
#include<random>
#include<cstdio>
#include<vector>
#include<bitset>
#include<stack>
#include<queue>
#include<deque>
#include<cmath>
#include<ctime>
#include<map>
#include<set>
//#include<ext/pb_ds/assoc_container.hpp>
//#include<ext/pb_ds/hash_policy.hpp>
//#include<ext/pb_ds/priority_queue.hpp>
#define fi first
#define se second
#define LD double
#define name(x) #x
#define ll long long
#define Vector Point
#define I128 __int128
#define ull unsigned ll
#define pii pair<int,int>
#define pb(x) push_back(x)
#define dek(x) debug(x)<<" "
#define deh(x) debug(x)<<endl
#define syt cerr<<"sytakioi\n"
#define debug(x) cout<<name(x)<<":"<<x
#define F(i,a,b) for(int i=a,i##end=b;i<=i##end;++i)
#define UF(i,a,b) for(int i=a,i##end=b;i>=i##end;--i)
#define look_memory cerr<<abs(&M2-&M1)/1024.0/1024<<'\n'
#define rd_i(l,r) uniform_int_distribution<int>(l,r)(rd)
#define rd_r(l,r) uniform_real_distribution<double>(l,r)(rd)
#define look_time cerr<<(clock()-Time)*1.0/CLOCKS_PER_SEC<<'\n'
using namespace std;
//using namespace __gnu_cxx;
mt19937 rd(time(0));
const int N=2005;
int n,m;
ll a[N],b[N];
bool M2;
int main(){
	int Time=clock();
	look_memory;
	cin.tie(nullptr)->sync_with_stdio(false);
	cin>>n>>m;
	F(i,1,n) cin>>a[i];
	F(t,1,m){
		int l,d;
		cin>>l>>d;
		a[l]+=d;
		F(i,1,n) b[i]=a[i];
		ll j=n,ans=0;
		UF(i,n,1) if(b[i]&1){
			--b[i];
			while(j&&b[j]<2) --j;
			if(j*2>i) b[j]-=2,++ans;
		}
		j=n;
		F(i,1,n){
			while(j){
				if(i==j){
					ans+=b[j]/3;
					break;
				}
				if(b[i]<=b[j]/2){
					ans+=b[i];
					b[j]-=b[i]*2;b[i]=0;
					break;
				}
				ans+=b[j]/2;
				b[i]-=b[j]/2;b[j]=0;
				--j;
			}
		}
		cout<<ans<<'\n';
	}
	look_time;
	return 0;
}