public class ChampaneTower {
public static void main(String[] args) {
System.out.println(champaneTower(5,3,1));
}

public static double champaneTower(int poured,int query_row,int query_glass){
	double[][] ca=new double[100][100];
	ca[0][0]=poured;
	for(int r=0;r<=query_row;r++){
		for(int l=0;l<=r;l++){
			double d=(ca[r][l]-1.0)/2;
			if(d>0){
				ca[r+1][l]+=d;
				ca[r+1][l+1]+=d;
			}
		}
	}
	return Math.min(1,ca[query_row][query_glass]);
}

}