#include <iostream>
constexpr int SIZE=524288, max_N=200001;
int tree[SIZE];
int t[max_N];

void update (int x){
    while (x!=0){
        tree[x]=tree[2*x]+tree[2*x+1];
        x/=2;
    }
}

int result (int station, int s, int pref){
    int o1=pref;
    int o2=s-o1;
    return s-2*std::min(o1,o2);
}

int solve (int s){
    int cr=1;
    int taken=0;
    while (cr<SIZE/2){
        if ((taken+tree[cr*2])*2<=s){
            taken+=tree[cr*2];
            cr=cr*2+1;
        }else{
            cr*=2;
        }
    }
    int station=cr-SIZE/2;
    return std::min(result(station,s,taken),result(station+1,s,taken+tree[cr]));
}

int main(){
    std::ios_base::sync_with_stdio(false);
    std::cout.tie(0);
    std::cout.tie(0);
    int n;
    std::cin>>n;
    int s=0;
    for (int i=1; i<n; ++i){
        std::cin>>t[i];
        t[i]*=2;
        tree[SIZE/2+i-1]=t[i];
        s+=t[i];
    }
    for (int i=SIZE/2-1; i>=1; --i)tree[i]=tree[2*i]+tree[2*i+1];
    std::cout<<solve(s)<<'\n';
    int k;
    std::cin>>k;
    int a, b;
    for (int i=0; i<k; ++i){
        std::cin>>a>>b;
        b*=2;
        tree[SIZE/2+a-1]=b;
        update((SIZE/2+a-1)/2);
        s+=b-t[a];
        t[a]=b;
        std::cout<<solve(s)/2<<'\n';
    }
}