3 +---+---+---+---+----+----+----+ +----+----+----+
--- of | C | H | I | C | K | E | N | => | C | H | I |
7 +---+---+---+---+----+----+----+ +----+----+----+
2 +---+---+---+ +-----+-----+
-- of | C | A | T | => | C | A |
3 +----+---+---+ +-----+-----+
1 +----+---+---+----+ +----+----+
-- of | G | O | A | T | => | G | O |
2 +----+---+---+----+ +----+----+
Accordingly, we must have:
+-----------+ +---------+ +------+ +----------------------------+
| C H I | + | C A | + | G O | => | C H I C A G O |
+-----------+ +---------+ +-------+ +----------------------------+