#include<iostream>
#include<string>

using namespace std;

int main(){

	int v=0,t;
	string vs;

	cin>>vs>>t;

	int z=1;
	for(int i=vs.size()-1;i>=0;i--){
		if(i==1) continue;
		v+=(vs[i]-'0')*z;
		z*=10;
	}
	cout<<v*t/10000<<endl;
}