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

void mainSolve()
{
        int N,U;
	cin >> N >> U;
	int to_send = N-U;
	cout << to_send << endl;
}

int main()
{
  int t=1;
  while (t--)
  {
    mainSolve();
  }
  return 0;
}