#include<stdio.h>
long i,j,la,lb,stan[201],ans[201];
char a[3001],b[3000001];
int main()
{
	FILE *fin,*fout;
	fin=fopen("writing.in","rb");
	fout=fopen("writing.out","wb");
	fscanf(fin,"%d%d\n",&la,&lb);
	for(i=1;i<=la;i++)
		fscanf(fin,"%c",&a[i]);
	fscanf(fin,"\n");
	for(i=1;i<=lb;i++)
		fscanf(fin,"%c",&b[i]);
	for(i=1;i<=200;i++)
	{
		stan[i]=0;
		ans[i]=0;
	}
	for(i=1;i<=la;i++)
		stan[a[i]]++;
	long num=0;
	for(i=1;i<=la;i++)
	{
		ans[b[i]]++;
	}
	for(i=1;i<=200;i++)
	{
		ans[i]=ans[i]-stan[i];
		if(ans[i]!=0)num++;
	}
	long all=0;
	if(num==0)all++;
	for(i=2;i<=lb-la+1;i++)
	{
		
		ans[b[i-1]]--;
		if(ans[b[i-1]]==0)num--;
		if(ans[b[i-1]]==-1)num++;
		ans[b[i+la-1]]++;
		if(ans[b[i+la-1]]==0)num--;
		if(ans[b[i+la-1]]==-1)num++;
		if(num==0)all++;
	}
	fprintf(fout,"%d",all);
	fclose(fin);
	fclose(fout);
	return 0;
}