#include
using namespace std;
int main()
{
int binary,mod,power=1,n;
int deci=0;
cin>>binary;
while(binary>0)
{
mod = binary%10;
deci = deci + (mod*power);
binary=binary/10;
power=power*2;
}
cout<<deci<<endl;
return 0;
}
i m not able to write no of lines then perform
