Definition: You are given a math word problem and you are supposed to apply addition or subtraction mathematical operators on the numbers embedded in the text to answer the following question and then only report the final numerical answer.

Positive Example 1 -
Input: Last year , 90171 people were born in a country , and 16320 people immigrated to it . How many new people began living in the country last year ?
Output: 106491

Positive Example 2 -
Input: There are 27 pencils in the drawer . Nancy placed 45 pencils in the drawer . How many pencils are now there in total ?
Output: 72

Negative Example 1 -
Input: Alyssa picked 42 pears and Nancy picked 17 pears from the pear tree . How many pears were picked in all ?
Output: 42

Negative Example 2 -
Input: The town of Milburg has 5256 grown - ups and 2987 children . How many people live in Milburg ?
Output: 2987

Now complete the following example -
Input: A worker at a medical lab is studying blood samples . 2 samples contained a total of 7341 blood cells . The first sample contained 4221 blood cells . How many blood cells were in the second sample ?
Output: 


Output: 3120