#include <iostream>
#include <string>
#include <stack>

using namespace std;

stack < float > st;

#define POP(f) if ( st.empty() ) cout << "Buffer underrun" << endl; else { f=st.top(); st.pop(); }

int main()
{
    while ( true )
    {
        string s;
        char  *tok;
        float f;

        getline( cin, s );

        tok = strtok( (char*)s.c_str(), " " );
        while ( NULL != tok )
        {
            if ( sscanf( tok, "%f", &f ))
                st.push( f );
            else
            {
                float f1, f2;
                POP(f2); POP(f1);

                switch( tok[0] )
                {
                case '+': st.push( f1+f2 ); break;
                case '-': st.push( f1-f2 ); break;
                case '*': st.push( f1*f2 ); break;
                case '/': st.push( f1/f2 ); break;
                default: cout << "invalid operation" << endl;
                }
            }
            tok = strtok( NULL, " " );
        }

        if ( st.size() == 1 )
        {
            cout << st.top() << endl;
            st.pop();
        } else
            return 1;
    }

    return 0;
}