#include <cstdio>

#define FIN "divk.in"
#define FOUT "divk.out"

#define MAX 500001
#define KMAX 100001

int N, K, A, B, R;
int V[MAX], S[MAX], C[KMAX];

int main()
{
    int i;

    freopen(FIN, "r", stdin);
    freopen(FOUT, "w", stdout);

    scanf("%d%d%d%d", &N, &K, &A, &B);

    for (i = 1; i <= N; ++ i)
    {
        scanf("%d", &V[i]);

        S[i] = (S[i - 1] + V[i]) % K;
    }

    for (i = A; i <= N; ++ i)
    {
        ++ C[S[i - A]];

        if (i > B)
            -- C[S[i - B - 1]];

        R += C[S[i]];
    }

    printf("%d\n", R);
}