Consider the following set of instructions: 0x400 ADDI X1, X1, #8
0x404 ORR X1, X1, X3
0x408 LDUR X7, [X1, #0]
0x40C ADD X1, X7, X4

Assume that in clock cycle N, instruction 0x400 is in IF stage, and that the register file writes to registers in the first half of the clock cycle and reads from registers in the second half. Assuming that the forwarding hardware does not exist, insert NOPs to eliminate data hazards. Calculate the CPI.