Split string at specific number

[TimeMen]

Uh, yes.
Here it is.

for i in range(0, len(pi)):
	x = int(pi[i])
	if  0 < x < 3:
		y = int(pi[i+1])
		if x == 1:
			char = int(pi[i] + pi[i+1]) + 65
			chars.append(chr(char))
		if x == 2 and y < 6:
			char = int(pi[i] + pi[i+1]) + 65
			chars.append(chr(char))
print(chars)

The problem is, that it iterates through the number, in this case Pi, but i can't jump twice if there is a number with two decimals which is contained in the alphabet.
Like 14. I can't jump twice to 15, so 4 is also counted as a character, but that not the goal.
Just considered whether a while loop could help me, because I can set the steps each round manually.

What do you think? Or is there any other more effective solution?

Yours Sincerely,
TimeMen