#include <bits/stdc++.h>
using namespace std;
long long res;
string s;
int n, k;
int a[100007];
long long fact[100007];
long long pot[100007];
long long sum[100007];
long long fpow(long long a, int w) {
  if (w == 0) return 1;
  if (w == 1) return a % 1000000007;
  if (w % 2)
    return fpow(a, w - 1) * a % 1000000007;
  else {
    long long q = fpow(a, w / 2);
    return q * q % 1000000007;
  }
}
long long inv(long long a) { return fpow(a, 1000000007 - 2); }
long long dwumian(int n, int k) {
  if (k > n) return 0;
  return fact[n] * inv(fact[k]) % 1000000007 * inv(fact[n - k]) % 1000000007;
}
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  fact[0] = pot[0] = 1;
  for (int i = 1; i < 100007; ++i) {
    fact[i] = fact[i - 1] * i % 1000000007;
    pot[i] = pot[i - 1] * 10 % 1000000007;
  }
  cin >> n >> k >> s;
  reverse((s).begin(), (s).end());
  for (int i = 0; i < n; ++i) {
    a[i] = s[i] - '0';
    sum[i] += a[i];
    sum[i] %= 1000000007;
    sum[i + 1] += sum[i];
  }
  for (int p = 0; p < n; ++p) {
    res += pot[p] * (sum[n - 1] - sum[p]) % 1000000007 *
           dwumian(n - p - 2, k - 1) % 1000000007;
    res += pot[p] * a[p] % 1000000007 * dwumian(n - p - 1, k) % 1000000007;
    res %= 1000000007;
    res += 1000000007;
    res %= 1000000007;
  }
  cout << res;
}
