#include <iostream> 
using namespace std;


double cac(double a,long long b){
	double result = 1;
	while(b){
		if(b&1){
			result = result*a;
		}
		b = b>>1;
		a = a*a;
	}
	return result;
}


double q(double d,long long w,long long c){  //d,wλ,c 
	double l,i,result;
	int m=2;
	for(i=0;i<w;i++){
		for(int j=9;j>-1;j--){
			result = d+(j/cac(10,c));
			l = result*result;
			if(l<m){
				d = result;
				c++; 
				break;
			}
		}
	}
	return d;
}


int main(){
	double a;
	long long w,c;
	cin>>a>>w>>c;
	printf("%.60f",q(a,w,c));
	return 0;
}