#include <cstdio>
#include <algorithm>
#include <vector>
#include <climits>
#include <cstring>

using namespace std;

const int MAX_N = 500000;
vector<int> ch[MAX_N];
int no2serial[MAX_N];
int serial2no[MAX_N];
int locInTrip[MAX_N];
int depth[MAX_N];
int nextSerial;
int N, M, C;
int rangeMin[MAX_N];


int init(const vector<int>& trip, int left, int right, int node)
{
    if(left == right){
        return rangeMin[node] = trip[left];
    }
    int mid = (left + right) / 2;
    int leftMin = init(trip, left, mid, node*2);
    int rightMin = init(trip, mid+1, right, node*2+1);
    return rangeMin[node] = min(leftMin, rightMin);
}

int query(int l, int r, int node, int nodeLeft, int nodeRight)
{
    if(r < nodeLeft || nodeRight < l) return INT_MAX;
    if(l <= nodeLeft && nodeRight <= r)
        return rangeMin[node];
    int mid = (nodeLeft + nodeRight) / 2;
    return min(query(l, r, node*2, nodeLeft, mid), query(l,r,node*2+1,mid+1,nodeRight));
}

void traverse(int here, int d, vector<int> &trip)
{
    no2serial[here] = nextSerial;
    serial2no[nextSerial] = here;
    nextSerial++;

    depth[here] = d;
    locInTrip[here] = trip.size();
    trip.push_back(no2serial[here]);

    for(int i=0; i<ch[here].size(); i++){
        traverse(ch[here][i], d+1, trip);
        trip.push_back(no2serial[here]);
    }
}

int LCA(int u, int v)
{
    int lu = locInTrip[u];
    int lv = locInTrip[v];

    if(lu > lv) swap(lu, lv);
    int lca = serial2no[query(lu,lv,1,0,2*N-2)];
    return depth[u] + depth[v] - 2 * depth[lca];
}



int main()
{
    scanf("%d", &C);
    while(C--){
        scanf("%d %d", &N, &M);
        int a, b;

        for(int i=0;i<=N;i++){
            ch[i].clear();
        }
        for(int i=1;i<=N-1;i++){
            scanf("%d", &a);

            ch[a].push_back(i);
        }

        vector<int> tr;
        traverse(0, 0, tr);

        init(tr, 0, 2*N-2, 1);

        for(int i=0;i<M;i++){
            scanf("%d %d", &a,&b);
            printf("%d\n", LCA(a,b));
        }
    }
    return 0;
}