#include<stdio.h>
#define N 500001
long long n,k,a,b,i,c[N],v[N],s[N],t;
int main()
{FILE *f=fopen("divk.in","r"),*g=fopen("divk.out","w");
fscanf(f,"%lld%lld%lld%lld",&n,&k,&a,&b);
for(i=1;i<=n;i++)
      {fscanf(f,"%lld",&c[i]),s[i]=s[i-1]+c[i];
      if(i>=b+1&&v[s[i-b-1]%k]>0)
              v[s[i-b-1]%k]--;
      if(i>=a)
              v[s[i-a]%k]++;
      t+=v[s[i]%k];}
fprintf(g,"%lld",t);
return 0;}