def first_recurring_char(s):
    array = []
    z = str
    if type(s) is str and s is not None:
        for i in s:
            array.append(i)
            k = + 1
            for j in array[0:k - 1]:
                if j == i:
                    p = +1
                    print(p)
                    if p > 1:
                        z = str(j)
    return z


print(first_recurring_char("вадвава"))