from collections import Counter
input()
socks, pairs = Counter(map(int,input().strip().split())), 0
for s in socks: pairs += socks[s]//2
print(pairs)

int count = 0;
    for(int i=0; i<n; i++){
        if(c[i]!=0){
             for(int j=i+1; j<n; j++){
                if(c[i]==c[j]){
                    count++;
                    c[j]=0;
                    break;
                    }
                }           
        }
    }
    printf("%d", count);

function sockMerchant(n, ar) {
var res = 0;
    ar.sort();
    for(let i=0; i<n;i++){
        if(ar[i] == ar[i+1]){
            i++;
                  res++;
           }
    }
return res;
}

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int c[] = new int[n];
        for(int c_i=0; c_i < n; c_i++){
            c[c_i] = in.nextInt();
        }
        Arrays.sort(c);
        int t=0;
        for (int i=0;i<n-1;i++){
            if(c[i]==c[i+1]){
                t++;
                i++;
            }
        }
        System.out.println(t);
    }
}