1. (2023·浙江模拟) 有如下 Python 程序段：

s=input() stack=[0]* len(s)；top=- 1；presign='+'；num=0 for i in range(len(s)):     if'0'<=s[i]<='9':         num=num*10+int(s[i])     if i==len(s)- 1 or s[i] in'+-*/':         if presign=='+':             top+=1             stack[top]=num         elifpresign=='-':             top+=1             stack[top]=-num         elifpresign=='*':             top+=1             stack[top]=stack[top- 1]*num         else:             top+=1             stack[top]=stack[top- 1]//num         presign=s[i]         num=0 print(sum(stack))     #sum 函数对 stack 中所有元素求和

若输入'5*4-6+10/3' ，程序运行后， 输出结果是(         )