Consider a three level memory system of the following specifications,
T1: Memory access time of level-1 memory = 10 ns/word
T2: Memory access time of level-2 memory = 15 ns/word
T3: Memory access time of level-3 memory = 200 ns/word
H1 = 0.8 (hit latency at level-1)
H2 = 0.9 (hit latency at level-2)
H3 = 1.0 (hit latency at level-3)
If the referred word is available in level-1 memory, it is handed over to the processor. If it is not available in level-1, then a 2-word block is to be moved from level-2 to level-1 and from level-1 it is given to the processor. If it is not present in level-2, a four-word block is first moved from level-3 to level-2 and then associated block is moved from level-2 to level-1. The average access time will be _________________ ns (integer value only).