import java.lang.Math
import java.math.BigDecimal

fun main(args: Array<String>) {
    val (a, b, x) = readLine()!!.split(" ").map { it.toDouble() }

    val half = a * a * b / 2
    when {
        half == x -> {
            val ans = Math.atan(b / a)
            println(Math.toDegrees(ans))
        }
        half < x -> {
            // 1/2 * a * a* tan = (aab-x)/a
            // tan = 2(aab-x)/aaa
            val ans = Math.atan(2 * (a * a * b - x) / (a * a * a))
            println(Math.toDegrees(ans))
        }
        else -> {
            val ans = Math.atan(2 * x / (b * b * a))
            println(90 - Math.toDegrees(ans))

        }
    }
}
