#include<cstdio>

const int Nmax=500000;
const int Kmax=100000;

long long v[Nmax+1];
long long f[Kmax+1];

int main()
{
 freopen("divk.in","r",stdin);
 freopen("divk.out","w",stdout);
 long long n,k,a,b;
 scanf("%lld %lld %lld %lld ",&n,&k,&a,&b);
 long long rez=0;
 for(long long i=1;i<=n;i++)
    {
     scanf("%lld ",&v[i]);
     v[i]=(v[i-1]+v[i])%k;
     if(i>=a)
        f[v[i-a]]++;
     if(i>b)
        f[v[i-b-1]]--;
     rez+=f[v[i]];
    }
 printf("%lld\n",rez);
return 0;
}