#include<stdio.h>
#define maxn 5001
long n,k,a,b,i,j;
long long s,v[maxn];
int t,r[100];
FILE *f,*g;
int main()
{f=fopen("divk.in","r");
g=fopen("divk.out","w");
fscanf(f,"%ld %ld %ld %ld",&n,&k,&a,&b);
for(i=1;i<=n;i++)
{fscanf(f,"%lld",&v[i]);v[i]=v[i]+v[i-1];}
for(i=0;i<=n;i++)
{t+=r[v[i]%k];
if(i-b+1>=0)
r[v[i-b+1]%k]--;
r[v[i-a+2]%k]++;
}
fprintf(g,"%d",t);
return 0;}