from collections import Counter
def sockMerchant(n, ar):
    # Write your code here
    count = 0
    socks = Counter(ar)
    for key, value in socks.items():
        if value >= 2:
            count += value//2
    
    return count 

int sockMerchant(int n, vector<int> ar) {
    unordered_map<int, int> frequencyMap;
    
    int nPairs = 0;
    
    for(int i = 0; i < ar.size(); ++i){
        frequencyMap[ar[i]] += 1;
        if(frequencyMap[ar[i]] % 2 == 0){
            nPairs +=1;
        }
    }
    
    return nPairs;
}

def sockMerchant(n, ar):
    d={i:ar.count(i) for i in set(ar)}
    res=0
    for i in d:
        if d[i] >= 2:
            res = res + d[i]//2
    return res

public static int sockMerchant(int n, List<int> ar)
    {
        int pairCount = 0;
        
        var groupList = ar.Order()
            .GroupBy(e => e)
            .Select(e => new { SockId = e.Key, Count = e.Count() })
        .ToList();
        
        foreach(var sockGroup in groupList)
        {
            pairCount += sockGroup.Count / 2;
        }
        
        return pairCount;
    }