num = gets.chomp.to_i
arr = gets.chomp.split.map(&:to_i)
ans = []
for i in 1...arr.length
  ans.push (arr[i] - arr[i-1]).abs unless arr[i] - arr[i-1] == 0
end
ans.push 0 if ans.length == 0
ans = ans.sort
puts ans[0]