#include<cstdio>
int v[500005],f[100005];
int main(){
freopen("divk.in","r",stdin);
freopen("divk.out","w",stdout);
int n,k,a,b,i;
long long rasp=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++)
v[i]=(v[i-1]+v[i])%k;
for(i=a;i<=n;i++){
f[v[i-a]]++;
if (i-b-1>=0)
f[v[i-b-1]]--;
rasp=rasp+1LL*f[v[i]];}
printf("%lld\n",rasp);
return 0;}