#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <algorithm>
#include <vector>
#define LIM 1<<17
/// TONI BO$$ was here
/// #MLC

using namespace std;
char BUF[LIM];
int poz;

inline char getChar(){
    poz++;
    if(poz>=LIM){
    	fread(BUF,LIM,1,stdin);
    	poz=0;
    }
    return BUF[poz];
}

inline int getNr(){
    int r=0, semn=1;
    char ch=getChar();
    while(isdigit(ch)==0 && ch!='-') ch=getChar();
    if(ch=='-'){
        semn=-1;
        ch=getChar();
    }
    while(isdigit(ch)!=0){
        r=r*10+semn*(ch-'0');
        ch=getChar();
    }
    return r;
}

int v[500001],s[100001];

int main()
{
    int n,k,a,b,i;
    long long rez=0;
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    n=getNr();
    k=getNr();
    a=getNr();
    b=getNr();
    for(i=1; i<=n; i++)
        v[i]=getNr();
    for(i=1; i<=n; i++)
        v[i]=(v[i]+v[i-1])%k;
    rez=0;
    for(i=1; i<=n; i++)
    {
        if(i>=a)
            s[v[i-a]]++;
        if(i>=b+1)
            s[v[i-b-1]]--;
        rez+=s[v[i]];
    }
    printf("%lld",rez);

    return 0;
}