#include <stdio.h>
#include <stdbool.h>
int is_alternating_pattern(int *mem, int k) {
// Write your pointer logic here
int ret = 1;
int* ptr = mem;
bool one_pattern = false;
if(*ptr == 1)
{
one_pattern = true;
}
ptr++;
int element = 0;
for(int i = 1;i <k; ++i)
{
if(one_pattern)
{
if(*ptr != element)
{
ret = 0;
break;
}
element = !element;
}
else
{
if(*ptr != !element)
{
ret = 0;
break;
}
element = !element;
}
ptr++;
}
return ret;
}
int main() {
int n, k, arr[100];
scanf("%d %d", &n, &k);
for (int i = 0; i < n; i++) {
scanf("%d", &arr[i]);
}
int res = is_alternating_pattern(arr, k);
printf("%d", res);
return 0;
}