#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define ll long long
#define file(name) \
if(fopen(name".inp", "r")) \
freopen(name".inp", "r", stdin), freopen(name".out", "w", stdout);
const int Mod = 1e6 + 3;
const int MAX = 1e6 + 5;
int n, k, a[MAX];
namespace sub1 {
bool check() {
return n <= 10;
}
void solve() {
int ans = 0;
for (int mask = 0; mask < (1 << n); ++mask) {
bool oke = true;
int sum = 0;
for (int i = 0; i < n; ++i) {
sum += (mask >> i & 1);
if(i >= k) sum -= (mask >> (i - k) & 1);
if(i + 1 >= k) oke &= a[i + 1 - k] == sum;
}
ans += oke;
}
cout << ans; exit(0);
}
}
void you_make_it(void) {
cin >> n >> k;
for (int i = 0; i < n - k + 1; ++i) cin >> a[i];
reverse(a, a + n - k + 1);
if(sub1::check()) sub1::solve();
}
signed main() {
#ifdef LOCAL
freopen("TASK.inp", "r", stdin);
freopen("TASK.out", "w", stdout);
#endif
auto start_time = chrono::steady_clock::now();
cin.tie(0), cout.tie(0) -> sync_with_stdio(0);
you_make_it();
auto end_time = chrono::steady_clock::now();
cerr << "\nExecution time : " << chrono::duration_cast <chrono::milliseconds> (end_time - start_time).count() << "[ms]" << endl;
return (0 ^ 0);
}
// Dream it. Wish it. Do it.
