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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>

int main(){
  char str[200] = {};
  long n = 0;
  long hofu[100] = {};
  long hofucnt = 0;
  long k = 0;
  long i = 0;
  long kaburi = 0;
  long ryotan = 0;
  long hoge = 0;
  long long count = 0;
  
  scanf(" %s",str);
  scanf("%ld",&k);
  //printf("%s",str);
  for(i=0;i<100;i++){
    if(str[i] != '\0'){
      n++;
    }else{
      break;
    }
  }
  //printf("%ld/",n);
  if(str[0] == str[n-1]){
    ryotan = 1;
  }
  
  hofu[0] = 1;
  hofucnt = 0;
  str[n] = str[0];
  for(i=1;i<n;i++){
    if(str[i-1] == str[i]){
      hofu[hofucnt]++;
    }else{
      hofucnt++;
      hofu[hofucnt]++;
    }
  }
  
  /*for(i=0;i<=hofucnt;i++){
    printf("%ld.",hofu[i]);
  } */
  if(!ryotan || hofucnt == 0){
    for(i=0;i<=hofucnt;i++){
      kaburi += hofu[i]/2;
    }
    count = k * kaburi;
  }else{
    for(i=1;i<=hofucnt-1;i++){
      kaburi += hofu[i]/2;
    }
    //printf("%ld/%ld/%ld/",kaburi,hofucnt,hofu[hofucnt] + hofu[0]);
    kaburi += (hofu[hofucnt] + hofu[0])/2;
    count = kaburi * (k) -((hofu[hofucnt] + hofu[0])/2)+ (hofu[0] / 2) + (hofu[hofucnt] / 2);
  }
  printf("%lld",count);
  return 0;
  //ssllsssssllsssssllsss
  //issiiissii
}