/*
TASK: EXCESS
LANG: C++
*/
#include<iostream>
using namespace std;
int main()
{
    int n,k,i,br=0;;
    cin>>n>>k;
    int p[n],t[n+2];
    
    for (i=0;i<=n+1;i++)
    {
        t[i]=0;
    }
        
    for (i=0;i<n;i++)
    {
        cin>>p[i];
        t[p[i]]++;
    }
    
    for (i=0;i<=n;i++)
    {
        if ( t[p[i]]>=1 && t[p[i]]<3 ) br++;
    }
    
    cout<<br-1<<endl;
    return 0;
}
