let calCost sy sx (map : char[][]) = 
    let cal y x = (sy - y) ** 2.0 + (sx - x) ** 2.0 |> sqrt       
    let mutable cost = 0.0
    for i in 1 .. map |> Array.length do
        for j in 1 .. map.[0] |> Array.length do 
            if map.[i-1].[j-1] = '1' then
                cost <- cost + (cal (i |> float) (j |> float))
    cost                

let H, W = 
    let t = stdin.ReadLine().Split()
            |> Array.map int
    in t.[0], t.[1]
    
let P = Array.init H (fun _ -> stdin.ReadLine().ToCharArray())

let mutable ans = 1 <<< 16 |> float
    
for i in 1 .. H do 
    ans <- min ans (calCost 0.0              (i |> float) P)
    ans <- min ans (calCost (W + 1 |> float) (i |> float) P)

for i in 1 .. W do 
    ans <- min ans (calCost (i |> float)              0.0 P)
    ans <- min ans (calCost (i |> float) (H + 1 |> float) P)

ans |> printfn "%A"