Steps:
1. Write the truth table: (input A, B, C, output F)
2. Draw Karnaugh map according to the truth table and get the simplest expression:
F=AB+BC+AC
3. Simplify the simplest expression into NAND-NAND type:
F = [(negative of AB) and (negative of BC) and (negative of AC)].
4. Draw a picture according to the above NAND-NAND expression.