Read until the end of the stdin is not working

[MuhammadSawalhy]

I have tried this snippet of code to read until the last line of input:

std::string a;
while(std::cin >> a) {
  // do something
}

And when I CompetiTestRun it resulted in TIMEOUT. But it works in the terminal with redirecting a file to the stdin of the program.

./main < input.txt

[xeluxee]

Please provide main.cpp and input.txt

[MuhammadSawalhy]

#include <bits/stdc++.h>

using namespace std;

int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  string a, b;

  while (cin >> a) {
    cin >> b;
    std::cout << a << " * " << b << std::endl;
  }

  return 0;
}

12
12
2
222222222222222222222222

[xeluxee]

Fixed with aa3bbfbd4432ef28f026148c99961811562c77ef