#include <bits/stdc++.h> using namespace std; int main() { cin.tie(NULL); cout.tie(NULL); ios_base::sync_with_stdio(false); int ar[6][2] = {}; int t, m; cin >> t >> m; while(t--) { int a, b; cin >> a >> b; ar[b - 1][a]++; } int ans = 0; for(int i = 0; i < 6;i++) { ans += (ar[i][0] + m - 1) / m; ans += (ar[i][1] + m - 1) / m; } cout << ans; }