#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N = 300 + 4;
int vt[22][N][N], vt1[22][N][N];
void fun () {
int n, k, m;
cin >> n >> m >> k;
vector<int> a(n + 1), b(m + 1);
int s = 0;
for (int i = 1; i <= n; i++) cin >> a[i], s += a[i];
for (int i = 1; i <= m; i++) cin >> b[i];
for (int i = 1; i <= n; i++) {
if (a[i] < k) {
cout << "Impossible";
return;
}
}
int l = m / 2, r = (m + 1) / 2;
for (int i = 0; i <= 21; i++)
for (int j = 0; j <= 202; j++) for (int k = 0; k <= 202; k++) vt[i][j][k] = vt1[i][j][k] = 1e18;
for (int mask = 0; mask < (1 << l); mask++) {
int sum = 0, cnt = 0, res = 0;
for (int i = 0; i < l; i++) {
if (mask >> i & 1) {
sum += min(n, b[i + 1]);
cnt++;
res += b[i + 1];
}
}
// cout << mask << " : " << res << ' ' << cnt << ' ' << sum << ' ';
// for (int i = 0; i < l; i++) cout << (mask >> i & 1);
// cout << endl;
vt[cnt][sum][res] = min(vt[cnt][sum][res], res);
}
for (int mask = 0; mask < (1 << r); mask++) {
int sum = 0, cnt = 0, res = 0;
for (int i = 0; i < r; i++) {
if (mask >> i & 1) {
sum += min(n, b[i + 1 + l]);
cnt++;
res += b[i + 1 + l];
}
}
// cout << mask << " : " << "res " << res << " sum " << sum << " cnt " << cnt << " : ";
// for (int i = 0; i < r; i++) cout << (mask >> i & 1);
// cout << endl;
vt1[cnt][sum][res] = min(vt1[cnt][sum][res], res);
}
for (int cnt = l; cnt >= 0; cnt--) {
for (int sum = 200; sum >= 0; sum--) {
for (int res = 200; res >= 0; res--) {
for (int mask = 0; mask < (1 << 3); mask++) {
int a = (mask & 1), b = (mask >> 1 & 1), c = (mask >> 2 & 1);
vt1[cnt][sum][res] = min(vt1[cnt][sum][res], vt1[cnt + a][sum + b][res + c]);
}
}
}
}
for (int cnt = l; cnt >= 0; cnt--) {
for (int sum = 200; sum >= 0; sum--) {
for (int res = 200; res >= 0; res--) {
for (int mask = 0; mask < (1 << 3); mask++) {
int a = (mask & 1), b = (mask >> 1 & 1), c = (mask >> 2 & 1);
vt[cnt][sum][res] = min(vt[cnt][sum][res], vt[cnt + a][sum + b][res + c]);
}
}
}
}
int mx = k * n;
int ans = 1e18;
for (int mask = 0; mask < (1 << l); mask++) {
int sum = 0, cnt = 0, res = 0;
for (int i = 0; i < l; i++) {
if (mask >> i & 1) {
sum += min(n, b[i + 1]);
cnt++;
res += b[i + 1];
}
}
int l1 = max(0LL, k - cnt), l2 = max(0LL, k * n - sum), l3 = max(0LL, s - res);
ans = min(ans, res + vt1[l1][l2][l3]);
// cout << mask << " : " << l1 << ' ' << l2 << ' ' << l3 << ' ' << vt1[l1][l2][l3] << " : ";
// for (int i = 0; i < l; i++) cout << (mask >> i & 1);
// cout << endl;
}
for (int mask = 0; mask < (1 << r); mask++) {
int sum = 0, cnt = 0, res = 0;
for (int i = 0; i < r; i++) {
if (mask >> i & 1) {
sum += min(n, b[i + 1 + l]);
cnt++;
res += b[i + l + 1];
}
}
int l1 = max(0LL, k - cnt), l2 = max(0LL, mx - sum), l3 = max(0LL, s - res);
ans = min(ans, res + vt[l1][l2][l3]);
}
if (ans == 1e18) cout << "Impossible";
else cout << ans - s;
}
signed main () {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int tt = 1;
//cin >> tt;
while (tt--) fun();
return 0;
}
