func main(text1: String = readLine()!, text2: String = readLine()!) {
    let prefix = text2[text2.startIndex]
    guard let firstIndex = text1.firstIndex(of: prefix) else { return print(text2.count) }
    var counter = 0
    for (i, j) in zip(text1[firstIndex...].indices, text2.indices) where text1[i] != text2[j] {
        counter += 1
    }
    print(counter)
}

main()