Macro prepare 

macro_rules! prepare {
    (@output ($dol:tt)) => { ... };
    (@debug ($dol:tt)) => { ... };
    (@normal ($dol:tt)) => { ... };
    (@interactive ($dol:tt)) => { ... };
    (@fast ($dol:tt)) => { ... };
    (fast) => { ... };
    () => { ... };
    (?) => { ... };
}

Prepare useful macros.

• prepare!();: default (all input scanner (sc!, sv!) + buf print (pp!, dg!))
• prepare!(fast);: fast stdin/stdout for valid input (sc!, sv!, pp!, dg!)
• prepare!(?);: interactive (line scanner (scln!) + buf print (pp!, dg!))