#include<fstream>
using namespace std;
int main()
{int n,k,a,b,v[100],i,p,s;
ifstream f("divk.in");
ofstream g("divk.out");
p=0;
s=0;
f>>n>>k>>a>>b;
for(i=1;i<=n;i++)
	f>>v[i];
if ( a>b)
	{i=a;
	a=b;
	b=i;}
	i=1;
do
{s=v[i];
	if (s%k!=0)
	{s+=v[i+1];
	i++;}
	else 
	{p++;
	 a++;
	 i=a;}
}
while (a!=b);
g<<p;
return 0;
f.close();
g.close();
}