finaL submission Codeforces

#creating three empty list
price=[]
amount=[]
products=[]
#declaring variables
optimal_price=0
minimum=120
#number of elements as input
n=int(input())
#iterating till the range
for j in range(n):
    sle,ele=input().split()
    sle=int(sle)
    ele=int(ele)
    amount.append(sle)
    price.append(ele)
#do a loop over price
for idx,item in enumerate(price):
    if(item>minimum):     #making a condition
        price[idx]=minimum
    else:
        minimum=price[idx]
#multiplication between  two lists
for num1,num2 in zip(price,amount):
    products.append(num1*num2)
for gle in range(0,len(products)):
    optimal_price=optimal_price+products[gle]
print(optimal_price)