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>

int main(){
   char s[101],c,d,e,f;
   long k,a;
   int i,l;
 
   scanf("%s",s);
   l=strlen(s);
   d=s[0];e=s[1];
   if (l>2) f=s[2];
   else     f='A';
   scanf("%ld",&k);
   if (l==1) {
      printf("%ld\n",k/2);
      return 0;
   }
   a=0;
   for (i=0;i<l-2;i++) 
      if (s[i]==s[i+1]) {
         for (c='a';c<='z';c++)
             if (s[i]!=c && s[i+2]!=c) break;
         s[i+1]=c;
         a++;
      }
   if (s[l-2]==s[l-1]) printf("%ld\n",(a+1)*k);
   else if (s[l-1]==s[0] && (d!=e || e==f)) printf("%ld\n",a*k+k-1);
   else printf("%ld\n",a*k);
   return 0;
}