#include <cstdio>
using namespace std;

const int MAX_N = 500002;
const int MAX_K = 100002;

int N, K, A, B;
int s[MAX_N], cnt[MAX_K];
long long sol;

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, val; i <= N; ++i) {
        scanf("%d", &val);
        s[i] = (s[i - 1] + val) % K;
    }

    for(int i = A; i <= N; ++i) {
        ++cnt[s[i - A]];
        if(i > B)
            --cnt[s[i - B - 1]];
        sol += cnt[s[i]];
    }

    printf("%lld\n", sol);

    return 0;
}