#include <cstdio>

using namespace std;
int s[500005];
int c[100005];
int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    int n,k,a,b,x,i,rez=0;
    scanf("%d%d%d%d",&n,&k,&a,&b);
    for(i=1;i<=n;++i)
    {
        scanf("%d",&x);
        s[i]=(s[i-1]+x)%k;
        if(i>=a)
            c[s[i-a]]++;
        if(i>b)
            c[s[i-b-1]]--;
        rez+=c[s[i]];
    }
    printf("%d\n",rez);
    return 0;
}