#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <functional>
#include <set>
#include <map>
using namespace std;
typedef long long int ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef set<ll> sll;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;
typedef vector<bool> vb;
#define rep(i, a, b) for (ll i = a; i < b; i++)
#define sz(a) (ll) a.size()
#define pb(a) push_back(a)
#define mp(a, b) make_pair(a, b)
ll N, K;
vvll g;
vvll rev_g;
vll propagate;
vb reached;
sll starts;
ll answ = 0;
void dfs(ll cur, bool force = false) {
if (reached[cur]) return;
if (!force) {
for (vll::iterator pre = rev_g[cur].begin(); pre != rev_g[cur].end(); pre++) {
if (!reached[*pre]) {
//cout << "pre " << *pre + 1 << " (" << cur + 1 << ")" << endl;
return;
}
}
if (propagate[cur] == 0) {
starts.insert(cur);
//cout << "make s " << cur + 1 << endl;
return;
}
}
reached[cur] = true;
for (vll::iterator nxt = g[cur].begin(); nxt != g[cur].end(); nxt++) {
propagate[*nxt] = max<ll>(propagate[*nxt], propagate[cur] - 1);
//cout << cur + 1 << " : " << *nxt + 1 << " (" << propagate[*nxt] << ")" << endl;
dfs(*nxt);
}
}
void iterate_starts() {
while (!starts.empty()) {
ll cur = *starts.begin(); starts.erase(starts.begin());
answ++;
//cout << "1 --> " << cur + 1 << endl;
propagate[cur] = K;
dfs(cur);
}
}
int main() {
cin.tie(NULL)->sync_with_stdio(false);
cin >> N >> K;
g.resize(N);
rev_g.resize(N);
propagate.resize(N, 0);
reached.resize(N, false);
rep(i, 0, N) {
ll tmpu, tmpv;
cin >> tmpu >> tmpv;
tmpu--; tmpv--;
g[tmpu].pb(tmpv);
rev_g[tmpv].pb(tmpu);
}
propagate[0] = K + 1;
dfs(0, true);
rep(i, 1, N) {
if (sz(rev_g[i]) == 0) {
starts.insert(i);
}
}
iterate_starts();
// push propagate
rep(i, 0, N) {
if (propagate[i] != 0) {
dfs(i, true);
iterate_starts();
}
}
// take care of closed loops without entry points...
rep(i, 0, N) {
if (!reached[i]) {
propagate[i] = K;
answ++;
//cout << "1 --> " << i + 1 << endl;
dfs(i, true);
iterate_starts();
}
}
// output answer
cout << answ << endl;
return 0;
}
