#include<cstdio>
using namespace std;

int v[500001], nr;

int main(){
	freopen("divk.in", "r", stdin), freopen("divk.out", "w", stdout);
	int N, K, A, B, i, lng, rest, r;
	scanf("%d %d %d %d", &N, &K, &A, &B);
	for (i = 0; i < N; i++) scanf("%d", &v[i]);
	
	for (i = 0, rest = 0; i < A; i++) 
			rest = (rest + v[i]) % K;
	
	for (lng = A, r = rest; lng <= B; lng++, r = (rest + v[lng - 1]) % K){
		if (r == 0) nr ++;		
		for (i = lng; i < N; i++){
			r = (r + v[i] - v[i - lng]) % K;
			if (r == 0) nr++;
		}
	}

	printf("%d", nr);
	return 0;
}