#include <cstring>
#include <queue>
using namespace std;
int n,k,a,b,x,s[500002],i,sol;
queue<int> r[100001];
int main(){
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    scanf("%d %d %d %d",&n,&k,&a,&b);
    for (i=1,s[0]=0;i<=n;++i){
        scanf("%d",&x);
        s[i]=(s[i-1]+x)%k;
        }
    for (i=a;i<=n;++i){
        x=s[i];
        while (!r[x].empty() && r[x].front()<i-b) r[x].pop();
        r[s[i-a]].push(i-a);
        sol+=r[x].size();
        }
    printf("%d",sol);
    return 0;
}