#include <fstream>
using namespace std;ifstream r("divk.in");ofstream w("divk.out");int v[500001],f[99999];int main(){int n,a,b,k;long long cnt=0;r>>n>>k>>a>>b;for(int i=1;i<=n;i++){int x;r>>x;v[i]=(v[i-1]+x)%k;if(i>=a)f[v[i-a]]++;if(i>b)f[v[i-b-1]]--;cnt+=f[v[i]];}w<<cnt;return 0;}