#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ long long x=1,s=0; char a[64] cin>>a; int l=strcpy(a) while(a!=0){ s+=(a[i]-'0')*x; x*=2; } cout<<s; return 0; }