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func isGood(n int) bool {
    var flag bool
    for n != 0 {
        d := n % 10
        n /= 10
        switch d {
        case 3,4,7:
            return false
        case 2,5,6,9:
            flag = true
        }
    }
    return flag
}

func rotatedDigits(N int) int {
    sum := 0
    for i := 1; i <= N; i++ {
        if isGood(i) {
            sum++
        }
    }
    return sum
}