Tower of Hanio problem code in golang

tower_of_hanoi.go

package main
import (
    "fmt"
    "os"
    "strconv"
)
var count int
func hanoi(n int, a, b, c string){
    if n == 1{
        count++
        fmt.Printf("%d: move sheet %d from %s to %s\n",count, n, a, c)
        return
    }

    hanoi(n-1, a, c, b)
    count++
    fmt.Printf("%d: move sheet %d from %s to %s\n", count, n, a,c)
    hanoi(n-1, b, a, c)
}
func main(){
    var n int = 3
    var err error
    if len(os.Args) == 2{
        n, err = strconv.Atoi(os.Args[1])
        if err != nil {
            fmt.Printf("%s\n", err.Error())
            os.Exit(-1)
        }
    }
    hanoi(n, "A", "B", "C")
}