#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int INF = 1e9 + 5;
const int maxN = 45;
bool dp1[maxN][maxN*maxN];
bool dp2[maxN][maxN*maxN];
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n, m, k;
cin >> n >> m >> k;
vector<int> a(n), b(m);
for(int& i : a) {
cin >> i;
}
for(int& i : b) {
cin >> i;
}
int ans = INF;
for(int i : a) {
if (i < k) {
cout << "Impossible\n";
exit(0);
}
}
int time = accumulate(a.begin(), a.end(), 0);
vector<int> small, big;
for(int i : b) {
if (i <= n) {
small.push_back(i);
} else {
big.push_back(i);
}
}
dp1[0][0] = true;
int sn = small.size();
for(int i = 1; i <= sn; i++) {
for(int j = 0; j < maxN*maxN; j++) {
dp1[i][j] |= dp1[i-1][j];
if (j-small[i-1] < 0) continue;
dp1[i][j] |= dp1[i-1][j-small[i-1]];
}
}
vector<int> sums;
for(int j = 0; j < maxN*maxN; j++) {
if (dp1[sn][j]) {
sums.push_back(j);
}
}
dp2[0][0] = true;
int bn = big.size();
for(int i = 1; i <= bn; i++) {
for(int j = 0; j < maxN*maxN; j++) {
dp2[i][j] |= dp2[i-1][j];
if (j-big[i-1] < 0) continue;
dp2[i][j] |= dp2[i-1][j-big[i-1]];
if (dp2[i][j]) {
int need = max((k-i) * n, time-j);
auto it = lower_bound(sums.begin(), sums.end(), need);
if (it != sums.end()) {
ans = min(ans, (j+*it)-time);
}
}
}
}
if (ans == INF) {
cout << "Impossible\n";
} else {
cout << ans << "\n";
}
return 0;
}
