Buggy python submission (verdict: Runtime Error):
while True:
    if "-"in inputEnzan or "+"in inputEnzan or "*"in inputEnzan :
        index=0
        while index <len(inputEnzan):
            if inputEnzan[index]=="-" or inputEnzan[index]=="+" or inputEnzan[index]=="*":
                if stack!=[]:
                    if inputEnzan[index]=="-":
                        inputEnzan[index]=stack[0]-stack[1]
                    elif inputEnzan[index]=="+":
                        inputEnzan[index]=stack[0]+stack[1]
                    else:
                        inputEnzan[index]=stack[0]*stack[1]
                    inputEnzan[index-1]="null"
                    inputEnzan[index-2]="null"
                    stack.clear()
                else:
                    pass
            else:
                stack.append(int(inputEnzan[index]))
                
            index+=1
        while True:
            if not "null" in inputEnzan:
                break
            inputEnzan.remove("null")   
    else:
        print(inputEnzan[0])
        break


Fixed submission:
class stack:
    def __init__(self):
        self.s = []
    def push(self, x):
        self.s.append(x)
    def pop(self):
        ret = self.s[-1]
        del self.s[-1]
        return ret
    def size(self):
        return len(self.s)

inputL = input().split()
s = stack()
for char in inputL:
    if char == '+':
        b = s.pop()
        a = s.pop()
        s.push(a+b)
    elif char == '-':
        b = s.pop()
        a = s.pop()
        s.push(a-b)
    elif char == '*':
        b = s.pop()
        a = s.pop()
        s.push(a*b)
    elif char == '/':
        b = s.pop()
        a = s.pop()
        s.push(a/b)
    else:
        s.push(int(char))
print(s.pop())

Buggy python submission (verdict: Runtime Error):
inputEnzan=input().split()
stack=[]
while True:
    if "-"in inputEnzan or "+"in inputEnzan or "*"in inputEnzan :
        index=0
        while index <len(inputEnzan):
            if inputEnzan[index]=="-" or inputEnzan[index]=="+" or inputEnzan[index]=="*":
                if stack!=[]:
                    if inputEnzan[index]=="-":
                        inputEnzan[index]=stack[0]-stack[1]
                    elif inputEnzan[index]=="+":
                        inputEnzan[index]=stack[0]+stack[1]
                    else:
                        inputEnzan[index]=stack[0]*stack[1]
                    inputEnzan[index-1]="null"
                    inputEnzan[index-2]="null"
                    stack.clear()
                else:
                    pass
            else:
                stack.append(int(inputEnzan[index]))
                
            index+=1
        while True:
            if not "null" in inputEnzan:
                break
            inputEnzan.remove("null")   
    else:
        print(inputEnzan[0])
        break


Fixed submission:
class stack:
    def __init__(self):
        self.s = []
    def push(self, x):
        self.s.append(x)
    def pop(self):
        ret = self.s[-1]
        del self.s[-1]
        return ret
    def size(self):
        return len(self.s)

inputL = input().split()
s = stack()
for char in inputL:
    if char == '+':
        b = s.pop()
        a = s.pop()
        s.push(a+b)
    elif char == '-':
        b = s.pop()
        a = s.pop()
        s.push(a-b)
    elif char == '*':
        b = s.pop()
        a = s.pop()
        s.push(a*b)
    elif char == '/':
        b = s.pop()
        a = s.pop()
        s.push(a/b)
    else:
        s.push(int(char))
print(s.pop())

Buggy python submission (verdict: Runtime Error):
inputEnzan=input().split()
stack=[]
while True:
    if "-"in inputEnzan or "+"in inputEnzan or "*"in inputEnzan :
        index=0
        while index <len(inputEnzan):
            if len(inputEnzan)==1:
                break
            if inputEnzan[index]=="-" or inputEnzan[index]=="+" or inputEnzan[index]=="*":
                if stack!=[]:
                    if inputEnzan[index]=="-":
                        inputEnzan[index]=stack[0]-stack[1]
                    elif inputEnzan[index]=="+":
                        inputEnzan[index]=stack[0]+stack[1]
                    else:
                        inputEnzan[index]=stack[0]*stack[1]
                    del inputEnzan[index-2]
                    del inputEnzan[index-2]
                    stack.clear()
                    index-=1
                else:
                    index+=1
            else:
                stack.append(int(inputEnzan[index]))
                index+=1   
    else:
        print(inputEnzan[0])
        break


Fixed submission:
class stack:
    def __init__(self):
        self.s = []
    def push(self, x):
        self.s.append(x)
    def pop(self):
        ret = self.s[-1]
        del self.s[-1]
        return ret
    def size(self):
        return len(self.s)

inputL = input().split()
s = stack()
for char in inputL:
    if char == '+':
        b = s.pop()
        a = s.pop()
        s.push(a+b)
    elif char == '-':
        b = s.pop()
        a = s.pop()
        s.push(a-b)
    elif char == '*':
        b = s.pop()
        a = s.pop()
        s.push(a*b)
    elif char == '/':
        b = s.pop()
        a = s.pop()
        s.push(a/b)
    else:
        s.push(int(char))
print(s.pop())

Buggy python submission (verdict: Time Limit Exceeded):
inputEnzan=input().split()

def keisan(inputEnzan):
    while True:
        stockFornumber=[]
        index=0
        length=len(inputEnzan)
        if length==1:
            break
        while index<length:
            if inputEnzan[index]=="+" or inputEnzan[index]=="-" or inputEnzan[index]=="*":
                if len(stockFornumber)==2:
                    if inputEnzan[index]=="+":
                        inputEnzan[index]=stockFornumber[0]+stockFornumber[1]
                        stockFornumber=[]
                        inputEnzan[index-1]="null"
                        inputEnzan[index-2]="null"

                    elif inputEnzan[index]=="-":
                        inputEnzan[index]=stockFornumber[0]-stockFornumber[1]
                        stockFornumber=[]
                        inputEnzan[index-1]="null"
                        inputEnzan[index-2]="null"

                    else:
                        inputEnzan[index]=stockFornumber[0]*stockFornumber[1]
                        stockFornumber=[]
                        inputEnzan[index-1]="null"
                        inputEnzan[index-2]="null"
                else:
                    pass

            else:
                stockFornumber.append(int(inputEnzan[index]))
            index+=1

        while "null" in inputEnzan:
            inputEnzan.remove("null")

    print(inputEnzan[0])

keisan(inputEnzan)     



Fixed submission:
class stack:
    def __init__(self):
        self.s = []
    def push(self, x):
        self.s.append(x)
    def pop(self):
        ret = self.s[-1]
        del self.s[-1]
        return ret
    def size(self):
        return len(self.s)

inputL = input().split()
s = stack()
for char in inputL:
    if char == '+':
        b = s.pop()
        a = s.pop()
        s.push(a+b)
    elif char == '-':
        b = s.pop()
        a = s.pop()
        s.push(a-b)
    elif char == '*':
        b = s.pop()
        a = s.pop()
        s.push(a*b)
    elif char == '/':
        b = s.pop()
        a = s.pop()
        s.push(a/b)
    else:
        s.push(int(char))
print(s.pop())