#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
#define INF 0x3f3f3f3f
#define eps 1e-8
typedef long long LL;

int a[20010];

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