#include <bits/stdc++.h>

using namespace std;
int v[500005],f[500005];
int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    int n,k,a,b,i,cnt=0;
    scanf("%d%d%d%d",&n,&k,&a,&b);
    for(i=1;i<=n;++i)
    {
        scanf("%d",&v[i]);
        v[i]+=v[i-1];
        v[i]%=k;
        if(a<=i)
            f[v[i-a]]++;
        if(b<i)
            f[v[i-b-1]]--;
        cnt+=f[v[i]];
    }
    printf("%d",cnt);
    return 0;
}