#include <cstdio>
#include <stdio.h>
#include <iostream>
#include <math.h>
#include <vector>
#include <queue>
#include <stack>
#include <deque>
#include <algorithm>
#include <utility>
#include <set>
#include <map>
#include <stdlib.h>
#include <cstring>
#include <string.h>
#include <string>
#include <sstream>
#include <assert.h>
#include <climits>
#include <sstream>
#include <numeric>
#include <time.h>
#include <limits.h>
#include <list>
#include <bitset>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <iomanip>
#include <complex>
#include <chrono>
#include <fstream>
#include <functional>
#include <unistd.h>
// #pragma GCC optimize("Ofast,no-stack-protector")
// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx,avx2,bmi,bmi2,lzcnt,popcnt")
#define lowbit(x) ((x) & -(x))
#define ml(a, b) ((1ll * (a) * (b)) % M)
#define tml(a, b) (a) = ((1ll * (a) * (b)) % M)
#define ad(a, b) ((0ll + (a) + (b)) % M)
#define tad(a, b) (a) = ((0ll + (a) + (b)) % M)
#define mi(a, b) ((0ll + M + (a) - (b)) % M)
#define tmi(a, b) (a) = ((0ll + M + (a) - (b)) % M)
#define tmin(a, b) (a) = min((a), (b))
#define tmax(a, b) (a) = max((a), (b))
#define iter(a) (a).begin(), (a).end()
#define riter(a) (a).rbegin(), (a).rend()
#define init(a, b) memset((a), (b), sizeof(a))
#define cpy(a, b) memcpy((a), (b), sizeof(a))
#define uni(a) a.resize(unique(iter(a)) - a.begin())
#define pb emplace_back
#define mpr make_pair
#define ls(i) ((i) << 1)
#define rs(i) ((i) << 1 | 1)
#define INF 0x3f3f3f3f
#define NIF 0xc0c0c0c0
#define eps 1e-9
#define F first
#define S second
#define AC cin.tie(0)->sync_with_stdio(0)
using namespace std;
typedef long long llt;
typedef pair<int, int> pii;
typedef pair<double, double> pdd;
typedef pair<llt, llt> pll;
typedef complex<double> cd;
// const int M = 998244353;
// random_device rm;
// mt19937 rg(rm());
// default_random_engine rg(rm());
// uniform_int_distribution<int> rd(INT_MIN, INT_MAX);
// uniform_real_distribution<double> rd(0, M_PI);
void db() { cerr << "\n"; }
template <class T, class... U>
void db(T a, U... b) { cerr << a << " ", db(b...); }
inline char gc()
{
const static int SZ = 1 << 16;
static char buf[SZ], *p1, *p2;
if (p1 == p2 && (p2 = buf + fread(p1 = buf, 1, SZ, stdin), p1 == p2))
return -1;
return *p1++;
}
void rd() {}
template <typename T, typename... U>
void rd(T &x, U &...y)
{
x = 0;
bool f = 0;
char c = gc();
while (!isdigit(c))
f ^= !(c ^ 45), c = gc();
while (isdigit(c))
x = (x << 1) + (x << 3) + (c ^ 48), c = gc();
f && (x = -x), rd(y...);
}
template <typename T>
void prt(T x)
{
if (x < 0)
putchar('-'), x = -x;
if (x > 9)
prt(x / 10);
putchar((x % 10) ^ 48);
}
const int N = 2e5 + 5, M = 2.6e4, B = 250;
int fa[N], po[N], *a1[M], *a2[M], in[N], ou[N], bs[N], dp[N];
vector<int> eg[N], mb[M];
inline void cg(int p, int v)
{
for (; p < N; p += lowbit(p))
bs[p] += v;
}
inline int qy(int p)
{
int res = 0;
for (; p; p -= lowbit(p))
res += bs[p];
return res;
}
inline int qy(int l, int r)
{
return qy(r) - qy(l - 1);
}
void dfs()
{
vector<int> sk(1, 1);
int ct = 0;
while (!sk.empty())
{
if (in[sk.back()])
ou[sk.back()] = ct, sk.pop_back();
else
{
in[sk.back()] = ++ct;
for (int v : eg[sk.back()])
sk.pb(v);
}
}
}
signed main()
{
int n, m, q, x, y;
scanf("%d%d%d%d", &n, &m, &q, &po[1]), mb[po[1]].pb(1);
for (int i = 2; i <= n; i++)
scanf("%d%d", &fa[i], &po[i]), eg[fa[i]].pb(i), mb[po[i]].pb(i);
dfs();
for (int p = 1; p <= m; p++)
{
if (mb[p].size() <= B)
continue;
a1[p] = new int[m + 1];
a2[p] = new int[m + 1];
fill(a1[p], a1[p] + m + 1, 0);
fill(a2[p], a2[p] + m + 1, 0);
for (int v : mb[p])
dp[v]++;
for (int i = 1; i <= n; i++)
dp[i] += dp[fa[i]], a1[p][po[i]] += dp[i];
fill(dp, dp + n + 1, 0);
for (int v : mb[p])
dp[v]++;
for (int i = n; i > 0; i--)
dp[fa[i]] += dp[i], a2[p][po[i]] += dp[i];
fill(dp, dp + n + 1, 0);
}
while (q--)
{
scanf("%d%d", &x, &y);
if (mb[x].size() > B)
prt(a1[x][y]);
else if (mb[y].size() > B)
prt(a2[y][x]);
else
{
for (int i : mb[y])
cg(in[i], 1);
int ans = 0;
for (int i : mb[x])
ans += qy(in[i], ou[i]);
prt(ans);
for (int i : mb[y])
cg(in[i], -1);
}
putchar('\n'), fflush(stdout);
}
}
