Problem:
Score : 300 points

Problem Statement

Given is a string S. Let T be the concatenation of K copies of S.
We can repeatedly perform the following operation: choose a character in T and replace it with a different character.
Find the minimum number of operations required to satisfy the following condition: any two adjacent characters in T are different.

Constraints

1 \leq |S| \leq 100

S consists of lowercase English letters.

1 \leq K \leq 10^9

K is an integer.

Input

Input is given from Standard Input in the following format:

S
K

Output

Print the minimum number of operations required.

Sample Input 1

issii
2

Sample Output 1

4

T is issiiissii. For example, we can rewrite it into ispiqisyhi, and now any two adjacent characters are different.

Sample Input 2

qq
81

Sample Output 2

81

Sample Input 3

cooooooooonteeeeeeeeeest
999993333

Sample Output 3

8999939997

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

ll f(string S){
  ll res=0;
  int i=1;
  while(1){
    if(i>=S.size())break;
    if(S[i-1]==S[i]){
      res++;
      i++;
    }
    i++;
  }
  return res;
}
    

int main(){
  string S;
  int K;
  cin >> S >> K;
  if(f(S+S)>f(S)*2){
    cout << f(S)*K+K-1 << endl;
    return 0;
  }else if(f(S+S)==f(S)*2){
    cout << f(S)*K << endl;
    return 0;
  } 
}