#include <cstdio>
#define DIM 500010
using namespace std;

int N, M, sol;
int V[DIM], P[DIM], S[DIM];

int main(){
	
	freopen("divk.in" ,"r", stdin );
	freopen("divk.out","w", stdout);
	
	scanf("%d %d %d %d", &N, &K, &A, &B);
	
	for(int i = 1; i <= N; i ++){
		
		scanf("%d", &V[i]);
		P[i] = ( P[i-1] + V[i] ) % K;
		
		if(i > A)
			S[ P[i-A-0] ] ++;
			
		if(i > B)
			S[ P[i-B-1] ] --;
			
		sol += S[ P[i] ];
	}
	
	printf("%d\n", sol);
	
	fclose(stdin );
	fclose(stdout);
	
	return 0;
}