#include <cstdio>
#define maxN 500005
using namespace std;
int n,i,k,a,b,v[maxN],s[maxN],fr[maxN],rasp;
int main()
{
    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++)
    {
        scanf("%d",&v[i]),s[i]=(s[i-1]+v[i])%k;
        if(i>=a) fr[s[i-a]]++;
        if(i>b) fr[s[i-b-1]]--;
        rasp+=fr[s[i]];
    }
    printf("%d",rasp);
    return 0;
}