#!/usr/bin/ruby

# solution of http://http://abstrusegoose.com/126
# Author: Yoann Guillot
# License: WTFPLv2

class Integer
	def prime?
		return false if self % 2 == 0 or self == 1
		(3..(Math.sqrt(self))).step(2) { |i| return false if self % i == 0 }
		true
	end
end

def firstprime(num, primelen)
	(num.length-primelen).times { |i|
		subnum = num[i, primelen].to_i
		return subnum if subnum.prime?
	}
end

def largestrighttruncatableprime
	pool = [0]
	nextgen = proc {
		ng = []
		pool.each { |p|
			(0..9).each { |e|
				ng << (p*10+e) if (p*10+e).prime?
			}
		}
		pool = ng if not ng.empty?	# implicit return true
	}
	nil while nextgen[]
	pool.max
end

pi, e = DATA.read.split('__END__').map { |d| d.gsub(/[^0-9]/m, '') }

# first 10-digits prime found in digits of e
puts "a#{firstprime(e, 10)}"

# first 10-digits prime found in digits of pi
puts "b#{firstprime(pi, 10)}"

# first 9-digits prime found in digits of pi
# + first 9-digits prime found in digits of e
# + largest right-truncatable prime
puts "c#{firstprime(pi, 9) + firstprime(e, 9) + largestrighttruncatableprime}"

__END__
http://www.eveandersson.com/pi/digits/
pi = 3.
14159265358979323846264338327950288419716939937510
58209749445923078164062862089986280348253421170679
82148086513282306647093844609550582231725359408128

__END__
http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/e_<dixmille>.html
e = 2.
718281828459045235360287471352662497757247093699959574966967627724076630353
547594571382178525166427427466391932003059921817413596629043572900334295260