# import sys; input = sys.stdin.buffer.readline
# sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")
import copy

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	v, t = list(input().split())

	vnew = ""
	for i in range(4):
		vnew += v[-1 - i]

	vnew = int(vnew[::-1])
	ans = vnew * int(t) // 10000
	print(ans)


if __name__ == '__main__':
	main()