def merge_st(S1, S2):
    """Merge two sorted Python Lists S1 and S2 into properly sized list S"""
    i = j = 0
    S = S1+S2
    while i+j < len(S):
        if j == len(S2) or (i < len(S1) and S1[i] < S2[j]):
            S[i+j] = S1[i]
            i = i+1
        else:
            S[i+j] = S2[j]
            j = j+1
    return S