uri 1318 Fake Tickets

//thanks God For Every Thing!
//contest link:
#include<bits/stdc++.h>
#define pi                      acose(-1)

typedef long long int           ll;
typedef double                  dl;
using namespace std;
const int mx = 1e2+5;


int main()
{
    int n, m;
    while(cin>>n>>m && n!=0 && m!=0)
    {
        int a[m], i, cnt=0;
        for(i=0; i<m; i++)
        {
            cin>>a[i];
        }
        int x, j;
        for(x=0; x<m; x++)
        {
            if((a[x]!=-1) && a[x+2]!= a[x+3])
            {
                for(j=x+1; j<m; j++)
                {
                    if(a[x]==a[j])
                    {
                        cnt++;
                        a[j]=-1;
                        break;
                    }

                }
            }

        }
        cout<<cnt<<endl;
    }
    return 0;
}