#include <bits/stdc++.h>
using namespace std;
long long g,s,tt,num,aa[55],bb[55];
char x[3005],a[3000005];
int main(){
	freopen("writing.in","r",stdin);
	freopen("writing.out","w",stdout);
	cin>>g>>s;
	cin>>x;cin>>a;
	for(int i=0;i<g;i++){
		if(x[i]>='a'&&x[i]<='z') aa[x[i]-'a'+1]++;
		else aa[x[i]-'A'+1+26]++;
	}
	for(int i=0;i<g-1;i++){
		if(a[i]>='a'&&a[i]<='z') bb[a[i]-'a'+1]++;
		else bb[a[i]-'A'+1+26]++;
	}
	for(int i=g-1;i<s;i++){
		tt=0;
		if(a[i]>='a'&&a[i]<='z') bb[a[i]-'a'+1]++;
		else bb[a[i]-'A'+1+26]++;
		for(int j=1;j<=52;j++){
			if(aa[j]!=bb[j]){
				tt=1;break;
			} 
		}
		if(tt==0) num++;
		if(a[i-(g-1)]>='a'&&a[i-(g-1)]<='z') bb[a[i-(g-1)]-'a'+1]--;
		else bb[a[i-(g-1)]-'A'+1+26]--;
	}
	cout<<num;
	return 0;
}