#include <stdio.h>
int is_alternating_pattern(int *mem, int k) {
// Write your pointer logic here
if (k < 1) {
return 0;
} else if (k < 2) {
return 1;
}
int pat1 = *mem;
mem++;
int pat2 = *mem;
if (pat2 == pat1){
return 0;
}
mem++;
int i = 2;
while (i < k) {
if (i % 2 == 0) {
if (*mem != pat1) {
return 0;
}
} else {
if (*mem != pat2) {
return 0;
}
}
i++;
mem++;
}
return 1;
}
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;
}