#include<stdio.h>
int v[500002],s[500002],m[500002];

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