def sockMerchant(n, ar):
    # Write your code here
    count=0
    dict_values={}
    for socks in ar:
        if socks in dict_values:
            dict_values[socks]+=1
        else:
            dict_values[socks]=1
    for socks,pairs in dict_values.items():
        if pairs>=2:
            count+=pairs//2
    return count