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 s[101];
    scanf("%s", s);
    int n=0;
    while(s[n] != '\0'){
        n++;
    }
    long long int k;
    scanf("%lld", &k);
    if(n == 1){
        printf("%lld", k/2);
    }else if(n == 2 && s[0] == s[1]){
        printf("%lld", k);
    }else{
        long long int a=0, b=0, c=0;
        char buf[103];
        for(int i=0; i<=n; i++){
            buf[i] = s[i];
        }
        for(int i=1; i<n; i++){
            if(buf[i-1] == buf[i]){
                buf[i] = '&';
                a++;
            }
        }
        b = a;
        if(buf[n-1] == buf[0]){
            b++;
        }
        c = b;
        if(buf[n-1] == '&'){
            c--;
        }
        long long int ans;
        if(k == 1){
            ans = a;
        }else if(k == 2){
            ans = a+b;
        }else{
            ans = a + (c*(k-2)) + b;
        }
        printf("%lld", ans);
    }

    return 0;
}