import sys
from math import sqrt

def debug(x, table):
    for name, val in table.items():
        if x is val:
            print('DEBUG:{} -> {}'.format(name, val), file=sys.stderr)
            return None

def solve():
    v, t = input().split()
    v = int(v[2:])
    t = int(t)
    d = v * t // 10000
    print(d)

if __name__ == '__main__':
    solve()