#include <vector>
#include <iostream>
using namespace std;
int main() {
int n,temp,count=0,max=0;
cin>>n;
vector<int> m(10001,0);
for(int i=0;i<n;i++) {
cin>>temp;
m[temp]++;
if(temp>max) {
max=temp;
}
}
for(int i=0;i<=max;i++) {
if(m[i]>0) {
i+=6;
count++;
}
}
cout<<count<<'\n';
return 0;
}
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