#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 303;
const int K = 300;
int a[N];
int dp[N][N];
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
memset(dp, 0x3f, sizeof dp);
int n, m, k;
cin >> n >> m >> k;
for (int i = 1;i <= n;i++) {
cin >> a[i];
}
dp[0][0] = 0;
ll ans = 0;
int sum = 0;
for (int j = 1;j <= m;j++) {
int b;
cin >> b;
sum += b;
for (int l = j - 1;l >= 0;l--) {
for (int i = K;i >= 0;i--) {
dp[l + 1][min(K, i + b)] = min(dp[l + 1][min(K, i + b)], dp[l][i] + b);
}
}
}
if (k > m) {
cout << "Impossible\n";
return 0;
}
for (int i = 1;i <= n;i++) {
if (sum < a[i]) {
cout << "Impossible\n";
return 0;
}
if (a[i] < k) {
cout << "Impossible\n";
return 0;
}
}
for (int i = 1;i <= m;i++) {
for (int j = K;j >= 0;j--) {
dp[i][j] = min(dp[i][j], dp[i][j + 1]);
}
}
// for (int i = 0;i <= K;i++) {
// for (int j = 0;j <= K;j++) {
// cout << dp[i][j] << " \n"[j == K];
// }
// }
for (int i = k + 1;i <= K;i++) {
for (int j = 0;j <= K;j++) {
dp[i][j] = min(dp[i][j], dp[i - 1][j]);
}
}
for (int i = 1;i <= n;i++) {
ans -= a[i];
ans += dp[a[i]][a[i]];
}
cout << ans << '\n';
return 0;
}
