#!/usr/bin/env python3
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:i+j+1]+'e-'+str(j))
        pos[i]+=0.45*(pos[i+j+1]*.1**j+x)
        pos[i]+=0.45*(neg[i+j+1]*.1**j+x)
        neg[i]+=0.45*(pos[i+j+1]*.1**j-x)
        neg[i]+=0.45*(neg[i+j+1]*.1**j-x)
    pos[i]+=x/10
    neg[i]-=x/10
print(pos[0])