#include <cstdio>

using namespace std;

const int nmx = 500002;
const int kmx = 100002;

int n,k,a,b,v[kmx],s[nmx],nr;
long long sum;

int main(){
    freopen("divk.in", "r", stdin);
    freopen("divk.out", "w", stdout);

    scanf("%d %d %d %d", &n, &k, &a, &b);
    for(int i = 1; i <= n; ++i){
        scanf("%d", &nr);
        s[i] = (s[i-1] + nr) % k;
    }

    for(int i = 1; i <= n; ++i){
        if(i-a+1 > 0)
            ++ v[s[i-a+1]%k];
        if(i-b > 0)
            -- v[s[i-b]%k];
        sum += v[s[i]%k];
    }

    printf("%lld\n", sum);

    return 0;
}