#include <bits/stdc++.h>
#include <fstream>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
struct custom_hash {static uint64_t splitmix64(uint64_t x) {x += 0x9e3779b97f4a7c15;x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;x = (x ^ (x >> 27)) * 0x94d049bb133111eb;return x ^ (x >> 31);}size_t operator()(uint64_t x) const {static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();return splitmix64(x + FIXED_RANDOM);}};
// string __fname = ""; ifstream in (__fname + ".in"); ofstream out (__fname + ".out");
// #define cin in
// #define cout out
#define int64 long long
#define uint64 unsigned long long
#define x first
#define y second
#define pb push_back
#define pii pair <int, int>
#define pii64 pair <int64, int64>
#define db(x) cout << "> " << #x << ": " << (x) << "\n"
#define qr queries()
#define yn(x) if (x) {ctn("Yes");}else {ctn("No");}
void solve(int);
void queries(){int n;cin >> n;for (int i = 1; i <= n; i++) solve(i);}
template<class T>T ceildiv(T a, T b) {return a / b + !!(a % b);}
template<class T>T gcd (T a, T b){return (b ? gcd(b, a % b): a);}
template<class T>T lcm (T a, T b){return a * b / gcd(a, b);}
// // // // // // // // // // // // // // // // // // // // // //
/* TEMPLATE - VANILLA */
// // // // // // // // // // // // // // // // // // // // // //
const int ddx[] = {-1, -1, 0, 1, 1, 1, 0, -1};
const int ddy[] = {0, 1, 1, 1, 0, -1, -1, -1};
const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, 1, 0, -1};
const double pi = 3.14159265359;
const double eps = 1e-6;
const int64 hash_inv = 940594066;
const int64 hash_p = 101;
const int64 mod = 1e9 + 7;
const int maxn = 303;
const int maxd = 1e5 + 1;
const int mitm = 1.1e6;
const int lg = 21;
int sp [mitm][lg];
int a[maxn], b[maxn];
bitset <maxd> dp;
int n,m,k;
void solve(int id){
return;
}
vector <pii> gen (int l, int r) {
vector <pii> v;
int len = (r - l + 1);
for (int i = 1; i < (1 << len); i++){
int sum = 0, pt = 0;
for (int j = 0; j < len; j++){
if (i & (1 << j)) {
pt+=min(n, b[j + l]);
sum+=b[j + l];
}
}
v.push_back({sum, pt});
}
return v;
}
int query (int l, int r) {
int k = __lg(r - l + 1);
return max(sp[l][k], sp[r - (1 << k) + 1][k]);
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout << fixed; cout << setprecision(10);
cin >> n >> m >> k;
int sa = 0;
for (int i = 0; i < n; i++){
cin >> a[i];
sa+=a[i];
}
for (int i = 0; i < m; i++){
cin >> b[i];
}
sort(a, a + n);
sort(b, b + m);
if (a[0] < k) {
cout << "Impossible";
return 0;
}
if (k == 1) {
dp[0] = 1;
for (int i = 0; i < m; i++){
dp |= dp << b[i];
}
for (int i = sa; i < maxd; i++){
if (dp[i]){
cout << i - sa << "\n";
return 0;
}
}
cout << "Impossible";
return 0;
}
int rs = 1e9;
vector <pii> p1 = gen(0, m / 2), p2 = gen(m / 2 + 1, m - 1);
sort(p1.begin(), p1.end());
sort(p2.begin(), p2.end());
int w = p2.size();
for (int i = 0; i < w; i++){
sp[i][0] = p2[i].y;
}
for (int j = 1; j < lg; j++){
for (int i = 0; i + (1 << j) - 1 < w; i++){
sp[i][j] = max(sp[i][j-1], sp[i + (1 << (j - 1))][j-1]);
}
}
for (auto [s, pt]: p1) {
if (s >= sa && pt >= n * k) rs = min(rs, s - sa);
}
for (auto [s, pt]: p2) {
if (s >= sa && pt >= n * k) rs = min(rs, s - sa);
}
for (auto [s, pt]: p1) {
int need = sa - s;
int idx = lower_bound(p2.begin(), p2.end(), make_pair(need, -1)) - p2.begin();
if (idx == (int) p2.size()) continue;
int need2 = n * k - pt;
int idx2 = idx;
if (need2 > 0) {
int l = idx, r = w - 1, f = -1;
while (l <= r) {
int mid = (l + r) / 2;
if (query(idx, mid) >= need2) {
f = mid;
r = mid - 1;
}
else {
l = mid + 1;
}
}
if (f == -1) continue;
rs = min(rs, s + p2[f].first - sa);
}
else rs = min(rs, s + p2[idx2].first - sa);
}
if (rs == 1e9) {
cout << "Impossible";
}
else cout << rs;
return 0;
}
