#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;
for (int j = 1;j <= m;j++) {
int b;
cin >> 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);
}
}
}
int mn = min(m, *min_element(a + 1, a + 1 + n));
int mx = *max_element(a + 1, a + 1 + n);
if (mn < k) {
cout << "Impossible\n";
return 0;
}
int res = 1e9;
for (int j = k;j <= mn;j++) {
for (int l = mx;l <= K;l++) {
res = min(res, dp[j][l]);
}
}
if (res == 1e9) {
cout << "Impossible\n";
return 0;
}
ll ans = 0;
for (int i = 1;i <= n;i++) {
ans -= a[i];
ans += res;
}
cout << ans << '\n';
return 0;
}
