#include <bits/stdc++.h>
using namespace std;
#define all(a) a.begin(),a.end()
#define pb push_back
#define vt vector
#define endl '\n'
typedef long long ll;
const ll mod=1e9+7;
const ll inf=mod;
const int N=5e6+4;
int n,m,k,a[N],b[N],used[N];
void solve(){
cin>>n>>m>>k;
for(int i=1; i<=n; ++i){
cin>>a[i];
}
sort(a+1,a+1+n);
for(int i=1; i<=m; ++i){
cin>>b[i];
}
if(k==1){
int sum=0;
for(int i=1; i<=n; ++i) sum+=a[i];
used[0]=1;
for(int i=1; i<=m; ++i){
for(int j=2000000; j>=b[i]; --j) used[j]=max(used[j],used[j-b[i]]);
}
int ans=mod;
for(int i=sum; i<=2000000; ++i) if(used[i]) ans=min(ans,abs(i-sum));
if(ans==mod){
cout<<"Impossible\n";
return;
}
cout<<ans<<endl;
return;
}
if(m<=15){
for(int mask=0; mask<(1<<m); ++mask){
vt<int>v;
for(int i=0; i<m; ++i) if(mask&(1<<i)) v.pb(b[i+1]);
sort(all(v));
int val=0,id=1;
for(int i=0; i<m; ++i){
int xx=v[i]-val;
while(id<=n && a[id]<=xx){
xx-=a[id];
val+=a[id];
++id;
}
}
}
}
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
int tt=1;
// cin>>tt;
while(tt--) {
solve();
}
}
