#include <bits/stdc++.h>
using namespace std;
const int MAXN = 41;
int a[MAXN], b[MAXN], dp[2][MAXN * MAXN][MAXN * MAXN];
int main(){
cin.tie(0)->sync_with_stdio(0);
int n, m, k; cin >> n >> m >> k;
int s_a = 0, s_b = 0;
for(int i=1; i<=n; i++){
cin >> a[i];
s_a += a[i];
}
for(int i=1; i<=m; i++){
cin >> b[i];
s_b += min(n, b[i]);
}
for(int i=1; i<=n; i++){
if(a[i] < k){
cout << "Impossible\n";
return 0;
}
}
for(int i=0; i<2; i++){
for(int sum_a=0; sum_a<=s_a; sum_a++){
for(int sum_b=0; sum_b<=s_b; sum_b++){
dp[i][sum_a][sum_b] = 1e9;
}
}
}
int ans = 1e9;
dp[0][0][0] = 0;
for(int i=1; i<=m; i++){
for(int sum_a=0; sum_a<=s_a; sum_a++){
for(int sum_b=0; sum_b<=s_b; sum_b++){
dp[i % 2][sum_a][sum_b] = min(
dp[1 - i % 2][sum_a][sum_b],
dp[1 - i % 2][max(0, sum_a - b[i])][max(0, sum_b - min(n, b[i]))] + max(0, b[i] - sum_a)
);
if(sum_a == s_a && dp[i % 2][sum_a][sum_b] >= 0 && sum_b >= n * k){
ans = min(ans, dp[i % 2][sum_a][sum_b]);
}
}
}
}
if(ans == 1e9){
cout << "Impossible\n";
return 0;
}
cout << ans << "\n";
return 0;
}
