#include <iostream>

#include <cstdio>

#include <cstring>

#define maxn 20000000

#define mm 1000000

using namespace std;

int hash[maxn]={};

char str[mm];

int news[mm]={};

int ans;

int n,nc;

int BKDRHash(char *key)

{

    int seed=nc;

    int p=;

    //cout<<"pass";

    while (*key)

    {

        p=p*seed+(news[(*key++)-'a']);

    }

    return (p & 0x7FFFFFFF);

}

void hashit (char *s)

{

    //memset(hash,0,sizeof hash);

    int i,j,k;

    char ch[mm];

    for (i=;s[i+n-];i++)

    {

        for (j=;j<n;j++)

         ch[j]=s[i+j];

        ch[j]='\0';

        //puts(ch);

        int k=BKDRHash(ch);

        k%=maxn;

        //cout<<k<<endl;

        if (!hash[k])

        {

         ans++;

         hash[k]=;

         //cout<<"pass"<<endl;

        }

    }

}

int main()

{

    while (scanf("%d %d",&n,&nc)!=EOF)

    {

        ans=;

        getchar();

        gets(str);

        int cnt=;

        int i,j;

        for (i=;str[i];i++)

        {

            if (news[str[i]-'a']==) //使用二十六进制

             news[str[i]-'a']=cnt++;

        }

        hashit(str);

        printf("%d\n",ans);

    }

}