#include <stdio.h>

int SP[500500], now[100100];

int main()
{
    int i, N, K, A, B;

    freopen("divk.in", "r", stdin);
    freopen("divk.out", "w", stdout);

    scanf("%d%d%d%d", &N, &K, &A, &B);
    for (i = 1; i <= N; i ++)
    {
        int x;
        scanf("%d", &x);
        SP[i] = (SP[i - 1] + x) % K;
    }

    long long sol = 0;
    for (i = A; i <= N; i ++)
    {
        now[SP[i - A]] ++;
        sol += now[SP[i]];
        if (i >= B)
            now[SP[i - B]] --;
    }

    printf("%lld", sol);
    return 0;
}