List/set

[janek30]

I'm stuck here :
 

list = [{"a","b","c","d"},{"k","f","r","c"},{"c","a","o","r"},{"m","p","l"},{"i","r","p","b"}]
for i in range(len(list)):
    for j in range(i+1,len(list)): 
        if list[i] & list[j]:
            print(list[i]&list[j]) 

I don't understand how to find the most resemblance and how and print their indexs........