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>
#include <string.h>

long long Count(char S[100], int K){
  int i, c, Sc;
  int s[100];
  long long C;
  c = C = 0;
  Sc = 1;
  for(i = 1;i < strlen(S);i++){
    if(S[i-1] == S[i]) Sc++;
    else{
      s[c++] = Sc;
      Sc = 1;
    }
  }
  s[c++] = Sc;
  if(strlen(S) != 1){
    for(i = 0;i < c;i++){
      C += (long long) (s[i] / 2) * K;
      s[i] %= 2;
    }
    if(s[0] * s[c-1] == 1 && S[0] == S[strlen(S)-1]) C += K - 1;
  }else C = K / 2;
  return C;
}
int main(void){
  int K;
  char S[100];
  scanf("%s", S);
  scanf("%d", &K);
  printf("%lld\n", Count(S, K));
  return 0;
}