下面C++代码执行后的输出是 ( ) 。

int main() {

int a[9] = {4, 2, 1, 5, 0, 6, 7, 9, 10};

int MEX = 0;

for ( ; ; MEX++) {

bool Find = false;

for (int i = 0; i < 9; i++)

if (a[i] == MEX)

Find = true;

if (!Find) break;

}

cout << "MEX：" << MEX;

}