#!/usr/bin/ruby
def isok(a)
	return false if a[0]==a[2]
	return (a[1]<a[0]&&a[1]<a[2]) || (a[1]>a[0]&&a[1]>a[2])
end

a=gets.split.map(&:to_i)
#if a[1]==1 && isok(a)
#	puts :INF
#else
	k=100000
	x=(1...k).count{|i|isok(a.map{|e|e%i})}
	y=(k..1000000).count{|i|isok(a.map{|e|e%i})}
	if y>0
		puts :INF
	else
		p x
	end
#end