#include <stdio.h>
#include <stdlib.h>
int nr[100001],s[500001];
int main()
{   FILE *fin,*fout;
    int n,k,a,b,i,x;
    long long rez;
    fin=fopen("divk.in","r");
    fout=fopen("divk.out","w");
    fscanf(fin,"%d %d %d %d",&n,&k,&a,&b);
    rez=0;
    for(i=1;i<=n;i++){
        fscanf(fin,"%d",&x);
        s[i]=(s[i-1]+x)%k;
        if(i>=a)
            nr[s[i-a]]++;
        if(i>b)
            nr[s[i-b-1]]--;
        rez+=nr[s[i]];
    }


    fprintf(fout,"%lld",rez);
    fclose(fin);
    fclose(fout);
    return 0;
}