#!/usr/bin/env python3
# @EXPECTED_RESULTS@: TIME_LIMIT_EXCEEDED, WRONG_ANSWER
s=input()
n=len(s)
pos,neg=[0]*(n+1),[0]*(n+1)
for i in range(n-1,-1,-1):
    x=0
    for j in range(n-i):
        x=float(s[:i+j+1])
        pos[i]+=0.45*(pos[i+j+1]+x*.1**j)
        pos[i]+=0.45*(neg[i+j+1]+x*.1**j)
        neg[i]+=0.45*(pos[i+j+1]-x*.1**j)
        neg[i]+=0.45*(neg[i+j+1]-x*.1**j)
    pos[i]+=x*.1**(n-i)
    neg[i]-=x*.1**(n-i)
print(pos[0])