#include<stdio.h>
#define ll long long

ll sol,n,a,b,k;
ll v[500004],f[100005];

int main ()
{
    ll i;
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    scanf("%lld%lld%lld%lld",&n,&k,&a,&b);
    for(i=1;i<=n;i++)
        scanf("%lld",&v[i]);
    for(i=1;i<=n;i++)
        v[i]=(v[i]+v[i-1])%k;
    b++;
    for(i=1;i<=n;i++)
    {
        if(i-a>=0)
            f[v[i-a]]++;
        if(i-b>=0)
            f[v[i-b]]--;
        sol+=f[v[i]];
    }
    printf("%lld\n",sol);
    return 0;
}