// #define _GLIBCXX_DEBUG
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define rep0(N) for (int COUNTER = 0; COUNTER < (int)(N); COUNTER++)
#define rep(i, N) for (int i = 0; i < (int)(N); i++)
#define rep1(i, N) for (int i = 0; i < (int)(N); i++)
#define rep2(i, START, GOAL) for (int i = (int)(START); i < (int)(GOAL); i++)
#define rep3(i, START, GOAL) for (int i = (int)(START); i > (int)(GOAL); i--)
#define all(CONTAINER) CONTAINER.begin(), CONTAINER.end()
#define rall(CONTAINER) CONTAINER.rbegin(), CONTAINER.rend()
#define from1(CONTAINER) CONTAINER.begin() + 1, CONTAINER.end()
#define rfrom1(CONTAINER) CONTAINER.rbegin(), CONTAINER.rend() - 1
#define pout(X) cout << X << " "
#define print(X) cout << X << "\n"
#define output(X) cout << X << "\n"
#define dbe(X) cerr << X << " "
#define dbel(X) cerr << X << "\n"
#define dberr(X) cerr << X << " "
#define dberrl(X) cerr << X << "\n"
#define db(X) cerr << #X << ":" << (X) << " "
#define dbl(X) cerr << #X << ":" << (X) << "\n"
#define db2(X, Y) cerr << #X << ":" << (X) << ", " << #Y << ":" << (Y) << " "
#define db2l(X, Y) cerr << #X << ":" << (X) << ", " << #Y << ":" << (Y) << "\n"
#define dbl2(X, Y) cerr << #X << ":" << (X) << "\n" << #Y << ":" << (Y) << "\n"
#define db3(X, Y, Z) cerr << #X << ":" << (X) << ", " << #Y << ":" << (Y) << " " << #Z << ":" << (Z) << " "
#define db3l(X, Y, Z) cerr << #X << ":" << (X) << ", " << #Y << ":" << (Y) << ", " << #Z << ":" << (Z) << "\n"
#define dbl3(X, Y, Z) cerr << #X << ":" << (X) << "\n" << #Y << ":" << (Y) << "\n" << #Z << ":" << (Z) << "\n"
#define dbp(PAIR) cerr << #PAIR << ":(" << PAIR.first << ", " << PAIR.second << ") "
#define dbpl(PAIR) cerr << #PAIR << ":(" << PAIR.first << ", " << PAIR.second << ")\n"
#define dbt3(TUPLE3) cerr << #TUPLE3 << ":(" << get<0>(TUPLE3) << ", " << get<1>(TUPLE3) << ", " << get<2>(TUPLE3) << ") "
#define dbt3l(TUPLE3) cerr << #TUPLE3 << ":(" << get<0>(TUPLE3) << ", " << get<1>(TUPLE3) << ", " << get<2>(TUPLE3) << ")\n"
#define dbt4(TUPLE4) cerr << #TUPLE4 << ":(" << get<0>(TUPLE4) << ", " << get<1>(TUPLE4) << ", " << get<2>(TUPLE4) << ", " << get<3>(TUPLE4) << ") "
#define dbt4l(TUPLE4) cerr << #TUPLE4 << ":(" << get<0>(TUPLE4) << ", " << get<1>(TUPLE4) << ", " << get<2>(TUPLE4) << ", " << get<3>(TUPLE4) << ")\n"
#define dbv(VEC) cerr << #VEC << ":{ "; for (auto ELEM : VEC) cerr << ELEM << ", "; cerr << "}\n"
#define dbvp(VP) cerr << #VP << ":{ "; for (auto PAIR : VP) cerr << "(" << PAIR.first << ", " << PAIR.second << "), "; cerr << "}\n"
#define dbvv(VV) cerr << #VV << ":{\n"; for (auto VEC : VV) { cerr << "{ "; for (auto ELEM : VEC) cerr << ELEM << ", "; cerr << "},\n"; } cerr << "}\n"
#define dbvvp(VVP) cerr << #VVP <<":{\n"; for (auto VP : VVP) { cerr << "{ "; for (auto PAIR : VP) { cerr << "(" << PAIR.first << ", " << PAIR.second << "), "; } cerr << "},\n"; } cerr << "}\n";
#define dbs(SET) cerr << #SET << "{ "; for (auto ELEM : SET) cerr << ELEM << ", "; cerr << "}\n";
#define dbsp(SP) cerr << #SP << "{ "; for (auto PAIR : SP) cerr << "(" << PAIR.first << ", " << PAIR.second << "), "; "}\n";
#define dbm(MAP) cerr << #MAP << ":{ "; for (auto PAIR : MAP) cerr << "(" << PAIR.first << ", " << PAIR.second << "), "; cerr << "}\n"
#define YN(f) cout << (f ? "YES" : "NO") << "\n"
#define Yn(f) cout << (f ? "Yes" : "No") << "\n"
#define yn(f) cout << (f ? "yes" : "no") << "\n"
using ll = long long;
using pii = pair<int, int>;using pll = pair<ll, ll>;using pdd = pair<double, double>;
using ti3 = tuple<int, int, int>;using tl3 = tuple<ll, ll, ll>;using td3 = tuple<double, double, double>;
using ti4 = tuple<int, int, int, int>;using tl4 = tuple<ll, ll, ll, ll>;using td4 = tuple<double, double, double, double>;
using vi = vector<int>;using vl = vector<ll>;using vd = vector<double>;using vs = vector<string>;using vb = vector<bool>;
using vvi = vector<vi>;using vvl = vector<vl>;using vvd = vector<vd>;using vvb = vector<vb>;
using vpii = vector<pii>;using vpll = vector<pll>;using vpdd = vector<pdd>;
using mii = map<int, int>;using mll = map<ll, ll>;
using si = set<int>;using sl = set<ll>;using ss = set<string>;
using spii = set<pii>;using spll = set<pll>;using spdd = set<pdd>;
// db

int next_combination(int bitint) {
	int x = bitint & -bitint; // bitの最下位の1 (Least Significant Bit)
	int y = bitint + x; // bit + LSB
	return (((bitint & ~y) / x) >> 1) | y; //
}

int main() {
	int N, K; cin >> N >> K;
	ll L, R; cin >> L >> R;
	int nb = (N + 1) / 2, nc = N / 2;
	vl b(nb); rep(i, nb) cin >> b[i];
	vl c(nc); rep(i, nc) cin >> c[i];
	// dbv(b); dbv(c);
	ll ans = 0;
	rep(t, K + 1) {
		// db2l(t, K-t);		
		if (nb < t) break;
		else if (nc < K - t) continue;
		vl Ub, Uc;
		if (t > 0) {
			for (int bit = (1 << t) - 1; bit < (1 << nb); bit = next_combination(bit)) {
				ll res = 0;
				rep(i, nb) if (bit & (1 << i)) res += b[i];
				Ub.push_back(res);
			}			
		}
		if (K - t > 0) {
			for (int bit = (1 << (K - t)) - 1; bit < (1 << nc); bit = next_combination(bit)) {				
				ll res = 0;
				rep(i, nc) if (bit & (1 << i)) res += c[i];
				Uc.push_back(res);
			}
		}
		sort(all(Ub)); sort(all(Uc));
		// dbv(Ub); dbv(Uc);
		if (t == 0) ans += upper_bound(all(Uc), R) - lower_bound(all(Uc), L);
		else if (K - t == 0) ans += upper_bound(all(Ub), R) - lower_bound(all(Ub), L);
		else {
			ll temp = 0;
			rep(i, Ub.size()) { // 2^t
				if (Ub[i] >= R) break;
				temp += upper_bound(all(Uc), R - Ub[i]) - lower_bound(all(Uc), L - Ub[i]);
			}			
			ans += temp;
			// db2l(temp, ans);
		}		
	}
	print(ans);	
}


Measured memory_bytes: 7704