1200

/*
rabin-karp算法

基本思想是：把该字符集当成一个整数来看待

比较字符串转化的整数来判断两个字符串是否相等

对于这个题目，有几个疑问，N如果很大，那么int不就超了嘛，可是却能AC.理论上 应该去摸一个大质数的

*/

// include file
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cctype>
#include <ctime>

#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <bitset>
#include <strstream>

#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <set>
#include <list>
#include <functional>

using namespace std;

// typedef
typedef long long LL;
typedef unsigned long long ULL;

// 
#define read freopen("in.txt","r",stdin)
#define write freopen("out.txt","w",stdout)
#define FORi(a,b,c) for(int i=(a);i<(b);i+=c)
#define FORj(a,b,c) for(int j=(a);j<(b);j+=c)
#define FORk(a,b,c) for(int k=(a);k<(b);k+=c)
#define FORp(a,b,c) for(int p=(a);p<(b);p+=c)

#define FF(i,a)    for(int i=0;i<(a);i+++)
#define FFD(i,a)   for(int i=(a)-1;i>=0;i--)
#define Z(a) (a<<1)
#define Y(a) (a>>1)

const double eps = 1e-6;
const double INFf = 1e10;
const int INFi = 1000000000;
const double Pi = acos(-1.0);

template<class T> inline T sqr(T a){return a*a;}
template<class T> inline T TMAX(T x,T y)
{
	if(x>y) return x;
	return y;
}
template<class T> inline T TMIN(T x,T y)
{
	if(x<y) return x;
	return y;
}
template<class T> inline void SWAP(T &x,T &y)
{
	T t = x;
	x = y;
	y = t;
}
template<class T> inline T MMAX(T x,T y,T z)
{
	return TMAX(TMAX(x,y),z);
}


// code begin
#define MAXN 16000001
int N,NC;
char in[20000000];
int len;
bool hash[MAXN];
int asc[300];
int ans;
// string search algorithm
void SSA_Rabin_Karp()
{
	memset(hash,0,sizeof(hash));
	
	int cur = 0;
	int first = 1;
	FORi(0,N,1)
	{
		cur = cur*NC+asc[in[i]];
		first = first*NC;
	}
	first = first/NC;
	//
	FORi(0,len-N+1,1)
	{
		if(!hash[cur])
		{
			hash[cur]=true;
			ans++;
		}
		if(i+N>=len) break;
		cur = (cur - asc[in[i]]*first)*NC+asc[in[i+N]];
	}
}

int main()
{
	read;
	write;
	while(scanf("%d %d",&N,&NC)!=-1)
	{
		//此处是NC进制
		scanf("%s",in);

		// 首先把相应的字符对应于一个0~NC-1
		int id = 0;
		len = strlen(in);
		memset(asc,-1,sizeof(asc));
		FORi(0,len,1)
		{
			if(asc[in[i]]==-1)
				asc[in[i]] = id++;
		}
		
		// 
		ans = 0;
		SSA_Rabin_Karp();
		printf("%d\n",ans);
	}
	return 0;
}