#include <fstream>

const int MAX_N = 5 * 1e5;
const int MAX_K = 1e5;
long long sp[1 + MAX_N], freq[1 + MAX_K];

class InParser {
private:
	FILE *fin;
	char *buff;
	int sp;

	char read_ch() {
		++sp;
		if (sp == 4096) {
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}

public:
	InParser(const char* nume) {
		fin = fopen(nume, "r");
		buff = new char[4096]();
		sp = 4095;
	}

	InParser& operator >> (int &n) {
		char c;
		while (!isdigit(c = read_ch()) && c != '-');
		int sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}

	InParser& operator >> (long long &n) {
		char c;
		n = 0;
		while (!isdigit(c = read_ch()) && c != '-');
		long long sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}
};

int main() {
  InParser fin("divk.in");
  std::ofstream fout("divk.out");
  int n, k, a, b;
  fin >> n >> k >> a >> b;
  for (int i = 1; i <= n; i++) {
    fin >> sp[i];
    sp[i] += sp[i - 1];
    sp[i] %= k;
  }
  int answer = 0;
  for (int i = a; i <= n; i++) {
    freq[sp[i - a]]++;
    if (i > b) {
      freq[sp[i - b - 1]]--;
    }
    answer += freq[sp[i]];
  }
  fout << answer;
  return 0;
}