//Yamero codeforces-chan/atcoder-chan/quera-chan
//#pragma GCC optimize ("O3,unroll-loops")
//#pragma GCC target ("avx2,bmi,bmi2,popcnt")
#include <bits/stdc++.h>
#define F first
#define pb push_back
#define sz size()
#define S second
using namespace std;
typedef long long int ll;
const int N = 1000;
int n,m,k,a[N],b[N];
bitset<N*N> dp;
inline void init(){
}
inline void input(){
cin >> n >> m >> k;
for(int i=0;i<n;i++)
cin >> a[i];
for(int i=0;i<m;i++)
cin >> b[i];
}
inline void solve(){
dp[0] = 1;
for(int i=0;i<m;i++)
dp |= (dp << b[i]);
int sum = 0;
for(int i=0;i<n;i++)
sum += a[i];
for(int i=sum;i<N*N;i++){
if(dp[i]){
cout << i - sum;
return;
}
}
cout << "Impossible";
}
int main(){
ios:: sync_with_stdio(0), cin.tie(0), cout.tie(0);
// freopen("input.txt", "r", stdin);
// freopen("output.txt", "w", stdout);
init();
int queries = 1;
// cin >> queries;
while(queries--){
input();
solve();
}
return 0;
}
