#include <cstdio>
#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <sstream>
#include <iomanip>
#include <cmath>
#include <cstdlib>
#include <ctype.h>
#include <cstring>
#include <ctime>

using namespace std;

#define MAXN 100005
#define MAXLOGN 20
vector<int> graph[MAXN];
int L[MAXN], T[MAXN];
int dp[MAXN][MAXLOGN];
int k, t, x, y, N, M, H;

void levels(int node, int level) {
    L[node] = level;
    H = max(H, level);

    for(size_t i = 0; i < graph[node].size(); i++)
        levels(graph[node][i], level + 1);
}

int go(int node, int p) {
    int bit = 0;
    while(p > 0) {
        if(p & 1) node = dp[node][bit];
        bit++;
        p /= 2;
    }

    return node;
}

int lca(int x, int y) {
    if(L[x] < L[y])
        y = go(y, L[y] - L[x]);
    else if(L[x] > L[y])
        x = go(x, L[x] - L[y]);

    if(x == y)
        return x;

    int m = 0;
    while(m <= MAXLOGN) {
        if(dp[x][m] == dp[y][m] && dp[x][m] != 0)
            return dp[x][m];
        m++;
    }

    return -1;
}

int main() {
	freopen("lca.in", "r", stdin);
	freopen("lca.out","w", stdout);

    scanf("%d %d", &N, &M);

    T[1] = 0;
    for(int i = 2; i <= N; i++) {
        scanf("%d", &t);
        graph[t].push_back(i);
        T[i] = t;
    }

    H = 0;
    levels(1, 0);

    for(int i = 1; i <= N; i++)
        dp[i][0] = T[i];
    for(int j = 1; (1 << j) < N; j++)
        for(int i = 1; i <= N; i++)
            dp[i][j] = dp[dp[i][j - 1]][j - 1];

    for(int i = 0; i < M; i++) {
        scanf("%d %d", &x, &y);

        printf("%d\n", lca(x, y));
    }

	return 0;
}