#include <bits/stdc++.h>
using namespace std;
const int MAXN = 310;
int a[MAXN], b[MAXN], dp[MAXN][MAXN * MAXN];
int main(){
cin.tie(0)->sync_with_stdio(0);
int n, m, k; cin >> n >> m >> k;
int s_a = 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];
}
for(int i=0; i<=m; i++){
for(int sum=0; sum<=s_a; sum++){
dp[i][sum] = 1e9;
}
}
dp[0][0] = 0;
for(int i=1; i<=m; i++){
for(int sum=0; sum<=s_a; sum++){
dp[i][sum] = min(dp[i - 1][sum], dp[i - 1][max(0, sum - b[i])] + max(0, b[i] - sum));
}
}
if(dp[m][s_a] == 1e9){
cout << "Impossible\n";
return 0;
}
cout << dp[m][s_a] << "\n";
return 0;
}
