import java.util.*;
import java.math.BigDecimal;
import java.math.RoundingMode;
public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        Scanner sc = new Scanner(System.in);
        double A = sc.nextDouble();
        double B = sc.nextDouble();
        
        BigDecimal C = new BigDecimal(String.valueOf(A));
        BigDecimal D = new BigDecimal(String.valueOf(B));
		BigDecimal F = new BigDecimal(String.valueOf(C.multiply(D)));

		BigDecimal G = F.setScale(0, RoundingMode.DOWN);
        System.out.println(G);
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz