Out of range. How to add the remainder of list to accumulator?

I get [-7,-4,-2], but I want to add the remaining numbers to my accumulator but I keep going out of range in my second if statement. How would I continue to add the remaining list? input: interleaved( [-7, -2, -1], [-4, 0, 4, 8])

def interleaved(seq1,seq2):
i = 0
j = 0
res = []

    

while i <len(seq1) and j <len(seq2):
    if seq1[i] < seq2[j]:
        res.append(seq1[i])
        i+=1
    if  seq2[j] <= seq1[i]:
        res.append(seq2[j])
        j+=1
return res