pythin计算该表达式的'值

puthon计算表达式的值，a为[1，9]，根据值和项数求和

def fun(n, m):
    if n<1 or n>9 or m <0: return 'ERR'
    s = 0
    for i in range(1, m+1):
        s += int(str(n)*i)
    return s

n, m = input().split(',')
print(fun(int(n),int(m)))