#include <stdio.h>

long long sol,n,k,a,b,v[500001],i,r[100001];

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