#!/usr/bin/env python3

# a_1 * (0.9 + 0.9 + 0.9 + 1)
mult=1
s = input()
n = len(s)
ans=0
for i,d in enumerate(s):
    ans+=(mult+0.9*(n-1-i)*mult)*int(d)
    mult*=0.1
print(ans)