#define _USE_MATH_DEFINES #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include typedef long long int ll; //#include using namespace std; ll gcd(ll a, ll b) { if (a < b)swap(a, b); if (b == 0)return a; return gcd(b, a % b); } int lcm(int a, int b) { return a * b / gcd(a, b); } int main() { int Q; Q = 1; //cin >> Q; while (Q--) { int n, m; cin >> n >> m; vectorf(n + 3); int ans = n; for (int i = 0; i < m; i++) { int a, b; cin >> a >> b; if (!f[b])ans--; f[b] = 1; } cout << ans; } return 0; }