# include <stdio.h>
long long n, K, A, B, lung, sol, i, cit;
long long v[500010], ap[100010];
int main (){
	freopen ("divk.in", "r", stdin);
	freopen ("divk.out", "w", stdout);
	scanf ("%lld%lld%lld%lld", &n, &K, &A, &B);
	for (i = 1; i <= n; ++i){
		scanf ("%lld", &cit);
		v[i] = (v[i - 1] + cit) % K;
	}
	for (i = 1; i <= n; ++i){
		if (i - A >= 0)
	    	++ap[v[i - A]];
		if (i - B >= 0){
			--ap[v[i - B - 1]];
		}
		sol = sol + ap[v[i]];
	}
	printf ("%lld\n", sol);
	return 0;
}