#include <bits/stdc++.h>
using namespace std;

int main() 
{
    int n;
    cin >> n;
    
    int k;
    cin >> k;
    
    string g;
    cin >> g;
    
    int count = 0;
    unordered_map<int, int> b;
    
    int p = 1;
    while (p <= 9)
    {
        int t = p * k; // 1*k = 1k , 2*k =2k ...till it will go till 10k
        
        if (t > n)
        {
            break;
        }
        
        b.clear(); // clear the frequency map for new window size or else it will get carry forward 
        
        for (int i = 0; i <= n - 1; i++)
        {
            if (i < t - 1)
            {
                //convert character to integer
                int number = g[i] - '0';
                b[number] = b[number] + 1; // basically we are storing in map 
            }
            else
            {
                //-------------jaise hee 'k' index pe aata Hu 'k' wala add kar deta hu -----------------------
                // convert the character to integer
                int number = g[i] - '0';
                b[number] = b[number] + 1;
                //--------------------------------
                
                int l = 0;
                int u = 0;
                
                while (l <= 9)
                {
                    if (b[l] == k || b[l] == 0)
                    {
                        // valid substring 
                    }
                    else
                    {
                        u = 1;
                        break;
                    }
                    
                    l = l + 1;
                }
                
                if (u == 0)
                {
                    count = count + 1;
                }
                
                //-----------uske just piche wala nikkal deta hu ...matlab window size 'k' maintain rehega proper answer aayega -----------------
                int y = g[i - t + 1] - '0';
                b[y] = b[y] - 1;
                //-----------------------------
            }
        }
        
        p++;
    }
    
    cout << count;
}