#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << " " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << " " << j << " " << #i << " " << q << " " << #p << endl;
#define show4(x,y) for(auto it:y) cout << it << " "; cout << #x << endl;
typedef pair<int,int>pii;
typedef pair<pii,pii>pi2;
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
int arr[305];
int n,m,k;
int chef[305];
int memo[305][100005];
int dp(int index, int take){
if(take>=k) return take-k;
if(index==m) return INT_MAX;
if(memo[index][take]!=-1) return memo[index][take];
int ans=INT_MAX;
ans=min(ans,dp(index+1,take));
ans=min(ans,dp(index+1,take+chef[index]));
return memo[index][take]=ans;
}
void solve(){
cin >> n >> m >> k;
int counter=0;
for(int x=0;x<n;x++){
cin >> arr[x];
counter+=arr[x];
}
for(int x=0;x<m;x++){
cin >> chef[x];
}
memset(memo,-1,sizeof(memo));
int hold=dp(0,0);
if(hold>1e8){
cout << "Impossible\n";
}
else cout << hold;
}
int32_t main(){
ios::sync_with_stdio(0);
cin.tie(0);
int t=1;
//cin >> t;
while(t--){
solve();
}
}
