#include <iostream>
#include<bits/stdc++.h>

using namespace std;

int main() {
	// your code goes here
	
	string word;
	cin>>word;
	int k;
	cin>>k;
	
	vector<int> dp(word.size(),0);
	dp[0]=1;
	for(int i=1;i<word.size();i++){
		if(abs(word[i]-word[i-1])<=k){
			dp[i]=dp[i-1]+1;
		}
		else{
			dp[i]=1;
			
		}
	}
	int answer = INT_MIN;
	for(int i=0;i<word.size();i++){
		answer = max(answer,dp[i]);
		
	}
	
	cout<<answer;
	
	return 0;
}