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(void) {
    int i, len, cnt, mastercnt;
    unsigned long k;
    char s[102];
    scanf("%s", s);
    len = strlen(s);
    s[len] = s[0];
    s[len+1] = '\0';
    scanf("%lu", &k);
    
    cnt = 0;
    mastercnt=0;
    for (i=1; i<=len; i++) {
        if (s[i-1] == s[i]) {
            cnt++;
            if (s[i] == s[i+1]) {
                i++;
                if (s[i+2] == '\0') {
                    break;
                }
            }
            if (s[i+1] == '\0') {
                if (cnt == 1) {
                    mastercnt=1;
                } else {
                    cnt--;
                }
            }
        }
    }

    printf("%lu", k*cnt+mastercnt);

    return 0;
}