import math._

object Main {
  def main(args: Array[String]) {
    val sc = new java.util.Scanner(System.in)

    var g, c, p = sc.nextInt
    val s = sc.next

    var ans = 0
    var ng = s.count(_ == 'G')
    var nc = s.count(_ == 'C')
    var np = s.count(_ == 'P')

    val mg = min(g, nc)
    val mc = min(c, np)
    val mp = min(p, ng)

    ans += 3 * (mg + mc + mp)
    g -= mg
    nc -= mg

    c -= mc
    np -= mc

    p -= mp
    ng -= mp

    ans += min(g, ng) + min(c, nc) + min(p, np)
    println(ans)
  }
}