#include <cstdio>

using namespace std;

int s[500005];
long long r[100001];

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

    int i,n,k,a,b;

    scanf("%d%d%d%d",&n,&k,&a,&b);
    long long sol=0LL;

    for(i=1;i<=n;i++)
    {
        scanf("%d",&s[i]);
        s[i]=(s[i]+s[i-1])%k;

        if(i>=a) r[s[i-a]]++;
        if(i>b) r[s[i-b-1]]--;

        sol+=r[s[i]];
    }

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


    return 0;
}