Duplicated words in a list

[pooyan89]

Hi!
I have a task:

Write a function called has_duplicates that takes a list and returns True if there is any element that appears more than once. It should not modify the original list.

Here is my attempt but I dont know why I do fail!

def has_dup(v):
    c=0
    
    for i in range(len(v)):
        for j in range(len(v)-1):
            if v[i]==v[j+1]:
                c=c+1
                print(c)
    if c>1:
        return True
    if c<=1:
        return False

If v=['car','bar','are']
Then has_dup(v) must be False but it gives me True every time ! why?
v[0] is not the same as v[1] or v[2], v[1] is not either the same like v[2], so why it increases the value of c ?