Problem:
Score : 200 points

Problem Statement

You are given a string S of length N consisting of lowercase English letters, and an integer K.
Print the string obtained by replacing every character in S that differs from the K-th character of S, with *.

Constraints

1 \leq K \leq N\leq 10

S is a string of length N consisting of lowercase English letters.

N and K are integers.

Input

Input is given from Standard Input in the following format:

N
S
K

Output

Print the string obtained by replacing every character in S that differs from the K-th character of S, with *.

Sample Input 1

5
error
2

Sample Output 1

*rr*r

The second character of S is r. When we replace every character in error that differs from r with *, we get the string *rr*r.

Sample Input 2

6
eleven
5

Sample Output 2

e*e*e*

Sample Input 3

9
education
7

Sample Output 3

******i**

Solution in Lua (5.3.2) (judge verdict: Accepted)

local function str2tbl(s)
    local t = {string.byte(s, 1, #s)}
    for i=1, #t do
        t[i] = string.char(t[i])
    end
    return t
end

local function str2numtbl(s, offset)
    local t = {string.byte(s, 1, #s)}
    if offset then
        for i=1, #t do
            t[i] = t[i] - offset
        end
    end
    return t
end

--local function each_char2(s)
--    return ipairs(str2tbl(s))
--end

local function each_char(s)
    local f = function(_, i)
        i = i + 1
        if i <= #s then
            return i, string.sub(s, i, i)
        end
    end
    return f, nil, 0
end

function string.at(s, i)
    return string.sub(s, i, i)
end

--
local N,_,S,K = io.read("n", "l", "l", "n")
local c = S:at(K)
local ans = string.gsub(S, "[^"..c.."]", "*")
print(ans)