# 행렬의 곱셈 - 프로그래머스
def solution(arr1, arr2):
ret = []
for i in range(len(arr1)):
row = []
for j in range(len(arr2[0])):
tmp = 0
for k in range(len(arr1[0])):
tmp += arr1[i][k] * arr2[k][j]
row.append(tmp)
ret.append(row)
return ret