/*
#include <iostream>
using namespace std;
int main()
{
int x1,x2,y1,y2;
int x3,x4,y3,y4;
cin>>x1>>y1>>x2>>y2;
cin>>x3>>y3>>x4>>y4;
if(x2==x3 && y2==y3)
cout<<"POINT";
if(x1==x4 && y1==y4)
cout<<"POINT";
if(y2<y3)
{
if(x2==x3 && y2==y3)
{
return 0;
}
if(x2<x3 || x2>x3)
{
cout<<"NULL";
}
}
if(x2==x3)
{
if(y2!=y3)
{
cout<<"LINE";
}
}
if(x1==x4)
{
if(y1!=y4)
{
cout<<"LINE";
}
}
if(x2>x3 && y2>y3)
{
if(x1<x4 && x1<x4)
cout<<"FACE";
}
}
*/
/*
#include <iostream>
#include<vector>
#include <string.h>
using namespace std;
string solution(vector<string>participant, vector<string>completion)
{
//cout << strcmp(participant[0],completion[0]);
string target ;
for(int i=0; i<participant.size(); i++)
{
for(int j=0; j<completion.size(); j++)
{
if(participant[i]!=completion[j])
{
cout<<participant[i] << endl;
}
}
}
return target;
}
int main()
{
vector <string> participant;
vector <string> completion;
participant.push_back("leo");
participant.push_back("kiki");
participant.push_back("eden");
completion.push_back("leo");
completion.push_back("kiki");
cout<<solution(participant, completion);
}
*/
#include <iostream>
using namespace std;
int main()
{
int arr[7][1001]={};
int n,k,a,b,num[7]={0},N=0,M=0,room=0,J;
cin>>n>>k;
for(int i=0; i<n; i++)
{
cin>>a>>b;
arr[b][num[b]]=a;
num[b]++;
}
for(int i=0; i<n; i++)
{
for(int j=1; j<=6; j++)
{
if(arr[j][i]==0)
{
N++;
if(N==k&&j==J)
{
N=0;
room++;
}
J=j;
}
if(arr[j][i]==1)
{
M++;
if(M==k&&j==J)
{
M=0;
room++;
}
J=j;
}
}
if(N!=0)
room++;
if(M!=0)
room++;
}
cout<<room;
}