#include using namespace std; int main(){ int a,b,c,d;cin>>a>>b>>c>>d; if(d > 9){ cout << "Impossible" << endl; }else{ long long ans = 0; long long nw = 1; while(a){ if(b >= 100){ ans += nw*(50*100); b-=100; }else if(a+b >= 100){ ans += nw*(b*50+(100-b)*100); a -= (100-b); b = 0; }else{ ans += nw*(b*50+a*100); break; } nw *= 2; } cout << ans << endl; } }