#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;

int a[20005];

int main(){
    int T, n, m;
    scanf("%d", &T);
    while(T--){
        int sum = 0;
        scanf("%d%d", &n, &m);
        for(int i = 1; i <= n; i++){
            scanf("%d", &a[i]);
        }
        for(int i = 1; i <=n; i++){
            for(int j = i+1; j <= n; j++){
                sum = sum^(a[i]+a[j]);
            }
        }
        while(m--){
            int x, y;
            scanf("%d%d", &x, &y);
            for(int i = 1; i <= n; i++){
                sum = sum^(a[x]+a[i])^(y+a[i]);
            }
            sum = sum^(a[x]+a[x])^(y+a[x]);
            a[x] = y;
            printf("%d\n", sum);
        }
    }
    return 0;
}