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[105];
	int K;
	int i;
	for(i=0;i<=104;i++)
	{
		S[i]='1';
	}
	scanf("%s",&S);
	scanf("%d",&K);
	int len;
	for(i=0;i<=104;i++)
	{
		if(S[i]!='1')
		{
			len=i;	
		}
	}
	int t;
	long int num=0;
	for(t=1;t<=len;t++)
	{
		if(S[t-1]==S[t])
		{
			S[t]='1';
			num+=1;
		}
	}
	if(S[0]!=S[len])
	{
		num=num*K;
	}
	else
	{
		int a;
		int time;
		for(a=2;a<=len;a++)
		{
			if(S[a-1]=S[a])
			{
				S[a]='1';
				time+=1;
			}
		}
		if(S[len]==S[0])
		{
			num=num+time*(K-1);
		}
		else
		{
			if(K%2==0)
			{
				num=(num+time)*K/2;
			}
			else
			{
				num=(num+time)*(K+1)/2-time;
			}
		}
	}
	printf("%ld",num);
	return 0;
}