let arr = readline().split(' ')
let n = arr.shift()
let k = arr.pop()
let x = arr.pop()
arr = arr.filter(el => el != x && Array.from(el).sort().join() == Array.from(x).sort().join())
let arrLen = arr.length
console.log(arrLen)
console.log(arrLen < k ? '' : arr.sort()[k-1])
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