void init(){

    for(ll x=n;x>=;x--){

        e[x].push_back();

        ll lc=x<<;ll rc=x<<|;

        if(lc<=n){

            for(int i=;i<e[lc].size();i++){

                e[x].push_back(e[lc][i]+len[lc-]);

            }

        }

        if(rc<=n){

            for(int i=;i<e[rc].size();i++){

                e[x].push_back(e[rc][i]+len[rc-]);

            }

        }

        sort(e[x].begin(),e[x].end());

        sum[x].resize(e[x].size());

        for(int i=;i<e[x].size();i++){

            sum[x][i]=sum[x][i-]+e[x][i];

        }

    }

}

ll query(int x,ll h){

    if(h<=)return ;

    int index=upper_bound(e[x].begin(),e[x].end(),h)-e[x].begin();

    return index*h-sum[x][index-];

}

int main()

{

//    freopen("in.txt","r",stdin);

    int m;

    scanf("%d%d",&n,&m);

    for(int i=;i<n;i++){

        scanf("%lld",&len[i]);

    }

    init();

    while(m--){

        ll a;

        ll h;

        ll pre=;

        scanf("%lld%lld",&a,&h);

        ll ans=;

        while(a&&h>){

            ans+=h;

            ll lc=a<<;

            ll rc=a<<|;

            if(lc!=pre&&lc<=n){

                ans+=query(lc, h-len[lc-]);

            }

        //    cout<<ans<<"\n";

            if(rc!=pre&&rc<=n){

                ans+=query(rc, h-len[rc-]);

            }

            //cout<<ans<<"\n";

            h-=len[a-];

            pre=a;

            a/=;

        }

        printf("%lld\n",ans);

    }

}