#include <stdio.h>
int is_alternating_pattern(int *mem, int k) {
// Write your pointer logic here
int result=1;
for(int i=0;i<k-2;i++)
{
if(i%2==0)
{
if(*(mem+i) != *(mem+i+2) )
{
result = 0;
}
}
else
{
if(*(mem+i) != *(mem+i+2))
{
result = 0;
}
}
}
return result;
}
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;
}