let mutable s = stdin.ReadLine ()
let t = stdin.ReadLine ()
let firstLength = s.Length
let length = t.Length

let findIndex (str: string) (search: string) =
    let mutable index = -1
    for i in 0..str.Length-search.Length do
        if index = -1 && str.[i..i+search.Length-1] = search then
            index <- i
    index
    
if length = 1 then
    if s |> Seq.contains t.[0] then
        printfn "-1"
    else
        printfn "0"
else
    while findIndex s t <> -1 do
        let index = findIndex s t
        s <- s.[..index+t.Length-2] + "." + s.[index+t.Length-1..]
    s.Length - firstLength |> printfn "%d"