// compile: make data
// run: ./data < data.in
#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#ifdef LOCAL
#include <debug/codeforces.h>
#define debug(x...) _debug_print(#x, x);
#define Debug(x...) _debug_print_format(#x, x);
#else
#define debug(x...)
#define Debug(x...)
#endif
template<typename...Args> void print_(Args...args){((cout<<args<<" "),...)<<endl;}
#define rep(i,a,b) for(int i=(a);i<(int)(b);++i)
#define sz(v) ((int)(v).size())
#define print(...) print_(__VA_ARGS__);
#define FIND(a, x) ((find(a.begin(),a.end(),(x))!=a.end())?1:0)
#define cmin(x,...) x=min({(x), __VA_ARGS__})
#define cmax(x,...) x=max({(x), __VA_ARGS__})
#define INTMAX (int)(9223372036854775807)
#define INF (int)(1152921504606846976)
#define double long double
#define int long long
#define MAXN 200010
#define N 18

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

    int n, q; cin >> n >> q;
    vector<int> a(n), root(n);
    vector<vector<int>> inv(n), flower;
    rep(i, 0, n) {
        int u; cin >> u; --u;
        a[i] = u, inv[u].push_back(i);
    }
    vector<int> dis(n, -1), comp(n, -1), pos(n, -1);
    vector<int> vis(n, 0);
    vector<vector<int>> parent(n, vector<int>(N));
    rep(i, 0, n) {
        if (~comp[i]) continue;
        vector<int> v;
        int x = i;
        for (; !~comp[x]; comp[x] = i, v.push_back(x), x = a[x]);
        int j; for (j = 0; j < sz(v) && v[j] != x; ++j);
        v = vector<int>(v.begin() + j, v.end());
        function<void(int, int, int)> dfs = [&](int u, int d, int rt) {
            if (vis[u]) return;
            vis[u] = 1, dis[u] = d, comp[u] = i, root[u] = rt;
            for (int vx: inv[u]) if (!~dis[vx]) dfs(vx, d + 1, rt);
        };
        rep(k, 0, sz(v)) pos[v[k]] = k, dis[v[k]] = 0;
        for (int k: v) dfs(k, 0, k);
        flower.push_back(v);
    }
    rep(i, 0, n) parent[i][0] = dis[i] ? a[i] : i;
    rep(j, 1, N) rep(i, 0, n) {
        parent[i][j] = parent[parent[i][j - 1]][j - 1];
        if (!dis[parent[i][j]]) parent[i][j] = root[i];
    }
    auto lca = [&](int u, int v) {
        if (dis[u] < dis[v]) swap(u, v);
        for (int i = N - 1; i >= 0; --i) if (dis[parent[u][i]] >= dis[v]) u = parent[u][i];
        if (u == v) return u;
        for (int i = N - 1; i >= 0; --i) if (parent[u][i] != parent[v][i]) u = parent[u][i], v = parent[v][i];
        return parent[u][0];
    };
    while (q--) {
        int u, v; cin >> u >> v; --u, --v;
        if (comp[u] != comp[v] || (!dis[u] && dis[v]) || (dis[u] && dis[v] && root[u] != root[v])) cout << -1 << endl;
        else if (!dis[u] && !dis[v]) cout << ((pos[v] >= pos[u]) ? pos[v] - pos[u] : sz(flower[comp[u]]) - pos[u] + pos[v]) << endl;
        else if (dis[u] && dis[v]) cout << ((lca(u, v) != v) ? -1 : dis[u] - dis[v]) << endl;
        else cout << dis[u] + ((pos[v] >= pos[root[u]]) ? pos[v] - pos[root[u]] : sz(flower[comp[root[u]]]) - pos[root[u]] + pos[v]) << endl;
    }

    return 0;
}