#include <bits/stdc++.h>

using  namespace  std;
string FillWithZeros(int nums)
{
    string text = "";
    for(int counter = 0; counter < nums; counter++)
    {
        text += "0";
    }
    return text;
}

int main()
{
    string firstNum, secondNum;
    cin>>firstNum;
    cin>>secondNum;
    bool secondIsBigger = false;
    if (secondNum.length() > firstNum.length())
    {
        string x = firstNum;
        firstNum = secondNum;
        secondNum = x;
        secondIsBigger = true;
    }
    if (firstNum.length() > secondNum.length())
    {
        int diff = firstNum.length() - secondNum.length();
        secondNum = FillWithZeros(diff) + secondNum;
    }
    else if (firstNum.length() < secondNum.length())
    {
        int diff = secondNum.length() - firstNum.length();
        firstNum = FillWithZeros(diff) + firstNum;
    }

    string result = "";

    if (secondNum.length() == firstNum.length())
    {
        for(int index = 0; index < firstNum.length(); index++)
        {
            if (secondNum[index] - 48 > firstNum[index] - 48)
            {
                string x = firstNum;
                firstNum = secondNum;
                secondNum = x;
                secondIsBigger = true;
            }
            else if (secondNum[index] - 48 < firstNum[index] - 48)
            {
                break;
            }
        }
    }
    for(int index = firstNum.length() - 1; index >= 0; index--)
    {
        int firstNumDigit = (int)firstNum[index] - 48;
        int secondNumDigit = (int)secondNum[index] - 48;
        if (firstNumDigit < secondNumDigit)
        {
            firstNum[index - 1]--;
            firstNumDigit += 10;
        }
        int diff = firstNumDigit - secondNumDigit;
        result = (char)(diff + 48) + result;
    }

    while(true)
    {
        if (result[0] == '0')
        {
            result = result.substr(1);
        }
        else
        {
            break;
        }
    }

    if (secondIsBigger)
    {
        result = "-" + result;
    }

    cout<<result<<endl;
return 0;

}