A, B = list(map(str, input().split())) # take the input in one line

A = int(A) # convert A into integer

C = B[0]+B[2]+B[3]

C = int(C)

print((A*C//100)) # printing the output



# time complixity O(1)
import math



if __name__ == "__main__":

    a, b = input().split()

    print((int(a)*int(b.replace('.', ''))//100))
A, B = list(map(str, input().split()))  # take the input in one line
A = int(A)  # convert A into integer
C = B[0] + B[2] + B[3]
C = int(C)
print((A * C // 100))  # printing the output
# time complixity O(1)

import math

if __name__ == "__main__":
    a, b = input().split()
    print((int(a) * int(b.replace(".", "")) // 100))

-A, B = list(map(str, input().split()))  # take the input in one line -A = int(A)  # convert A into integer -C = B[0] + B[2] + B[3] -C = int(C) -print((A * C // 100))  # printing the output -# time complixity O(1) +import math + +if __name__ == "__main__": +    a, b = input().split() +    print((int(a) * int(b.replace(".", "")) // 100))