#include<stdio.h>
#define NMAX 500000
int n,k,a,b,sp[NMAX+10],f[NMAX+10];
int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    int start,end,x,i;
    long long res=0;
    scanf("%d%d%d%d",&n,&k,&a,&b);
    for(i=1;i<=n;i++)
        {
            scanf("%d",&x);
            sp[i]=(x+sp[i-1])%k;
        }
    res=0;
    for(i=1;i<=n;i++)
        {
            if(i-a>=0)
                f[sp[i-a]]++;
            if(i-b>0)
                f[sp[i-b-1]]--;
            res=res+(long long)f[sp[i]];
        }
    printf("%d\n",res);
    return 0;
}