/* Author haleyk10198 */
/* 作者:  haleyk10198 */
#include <bits/stdc++.h>

#define MOD 1000000007
#define LINF (1LL<<60)
#define INF 2147483647
#define PI 3.1415926535897932384626433
#define ll long long
#define pii pair<int,int>
#define mp(x,y) make_pair((x),(y))
#define MAXN 262144

using namespace std;

string itos(int x){
	stringstream ss;
	ss << x;
	return ss.str();
}

map<char, int> m1;
const string gene = "ACGT";
string s, t;

int n, m, k, rescnt;

vector<complex<double> > vs[4], vt[4];

void fft(vector<complex<double> > &x){
	int n = x.size();
	if(n == 1)
		return ;
	vector<complex<double> > v[2];
	for(int i = 0; i < n; i++)
		v[i%2].push_back(x[i]);
	for(int i = 0; i < 2; i++)
		fft(v[i]);
	for(int i = 0 ; i < n/2; i++){
		double ar = 2*PI*i/n;
		complex<double> a, b, now = complex<double>(cos(ar), sin(ar));
		a = v[0][i];
		b = now*v[1][i];
		x[i] = a+b;
		x[i+n/2] = a-b;
	}
}

void ifft(vector<complex<double> > &x){
	int n = x.size();
	if(n == 1)
		return;
	vector<complex<double> > v[2];
	for(int i = 0; i < n; i++)
		v[i%2].push_back(x[i]);
	for(int i = 0; i < 2; i++)
		fft(v[i]);
	for(int i = 0 ; i < n/2; i++){
		double ar = -2*PI*i/n;
		complex<double> a, b, now = complex<double>(cos(ar), sin(ar));
		a = v[0][i];
		b = now*v[1][i];
		x[i] = a+b;
		x[i+n/2] = a-b;
	}
	for(auto &y: x)
		y /= n;
}

int main(){
	//freopen("input.txt","r",stdin);
	//freopen("output.txt","w",stdout);
	ios_base::sync_with_stdio(false);
	for(auto x: gene){
		int sz = m1.size();
		m1[x] = sz;
	}
	cin >> n >> m >> k >> s >> t;
	{
		for(int i = 0; i < 4; i++)
			vs[i] = vector<complex<double> >(MAXN, 0);
		{
			vector<int> lst = vector<int>(4, -MOD);
			int st = MAXN-n;
			for(int i = 0; i < n; i++){
				lst[m1[s[i]]] = i;
				for(int j = 0; j < 4; j++)
					if(lst[j]+k >= i)
						vs[j][st+i] = 1;
			}
			lst = vector<int>(4, MOD);
			for(int i = n; i; ){
				--i;
				lst[m1[s[i]]] = i;
				for(int j = 0; j < 4; j++)
					if(lst[j]-k <= i)
						vs[j][st+i] = 1;
			}
			st = MAXN - m;
			for(int i = 0; i < 4; i++)
				vt[i] = vector<complex<double> >(MAXN, 0);
			for(int i = 0; i < m; i++)
				vt[m1[t[i]]][i+st] = 1;
		}
		for(int i = 0; i < 4; i++)
			reverse(vt[i].begin(), vt[i].end());
	}
	for(int i = 0; i < 4; i++){
		fft(vs[i]);
		fft(vt[i]);
		for(int j = 0; j < MAXN; j++)
			vs[i][j] *= vt[i][j];
		ifft(vs[i]);
	}
	for(int i = 0; i < MAXN; i++){
		int tt = 0;
		for(int j = 0; j < 4; j++)
			tt += round(vs[j][i].real());
		if(tt == m)
			rescnt++;
	}
	cout << rescnt << endl;
	return 0;
}