#include <bits/stdc++.h>
using namespace std;

inline int read()
{
    int x = 0, f = 1;
    char ch = getchar();
    while(ch < '0' || ch >'9')
	{
        if(ch == '-')
		{
         	f = -1;
		}
        ch = getchar();
    }
    while(ch >= '0' && ch <= '9')
	{
        x = (x << 1) + (x << 3) + (ch ^ 48);
        ch = getchar();
    }
    return x * f;
}


int main()
{
    int a, b;
    a = read();
    b = read();
    int dig[3];
    dig[0] = a / 100;
    dig[1] = a % 100 / 10;
    dig[2] = a % 10;
    if (dig[0] != 9)
    {
    	dig[0] = 9;
	}
	else
	{
		if (dig[1] == 9)
		{
			dig[2] = 9;
		} 
		else
		{
			dig[1] = 9;
		}
	}

    int c = dig[0] * 100 + dig[1] * 10 + dig[2];
    cout << c - b << endl;
	return 0;
}