diff --git a/src/app.js b/src/app.js
index ad9a93a..edf9845 100644
--- a/src/app.js
+++ b/src/app.js
@@ -1 +1,61 @@
 'use strict';
+
+const { getRandomDigits } = require('./generateRandom.js');
+const { terminal } = require('./terminal.js');
+const { check } = require('./cheacker.js');
+const { isValidGuess } = require('./guessValidation.js');
+
+const startGame = () => {
+  const number = getRandomDigits();
+
+  const tryToGuess = () => {
+    terminal.question('Enter a number with 4 different digits: ', (guess) => {
+      const matches = check(number, guess);
+
+      if (isNaN(guess)) {
+        // eslint-disable-next-line no-console
+        console.log('Invalid input. Please enter 4 different digits.');
+        tryToGuess();
+
+        return;
+      }
+
+      if (guess.length !== 4 || !isValidGuess(guess)) {
+        // eslint-disable-next-line no-console
+        console.log('Not valid number!');
+        tryToGuess();
+
+        return;
+      }
+
+      if (!matches.bull && !matches.cow) {
+        // eslint-disable-next-line no-console
+        console.log('Try again!');
+        tryToGuess();
+
+        return;
+      }
+
+      if (matches.bull === 4) {
+        // eslint-disable-next-line no-console
+        console.log('Congratulations!');
+        terminal.close();
+
+        return;
+      }
+
+      if (matches.bull !== 4) {
+        // eslint-disable-next-line no-console
+        console.log(`
+        Nice try!
+        You have ${matches.bull} bulls and ${matches.cow} cows
+        `);
+        tryToGuess();
+      }
+    });
+  };
+
+  tryToGuess();
+};
+
+startGame();
diff --git a/src/cheacker.js b/src/cheacker.js
new file mode 100644
index 0000000..1483864
--- /dev/null
+++ b/src/cheacker.js
@@ -0,0 +1,25 @@
+'use strict';
+
+const check = (number, guess) => {
+  const obj = {
+    bull: 0,
+    cow: 0,
+  };
+  const numberStr = number.toString();
+
+  guess.split('').forEach((digit, i) => {
+    if (numberStr[i] === digit) {
+      obj.bull += 1;
+
+      return;
+    }
+
+    if (numberStr.includes(digit)) {
+      obj.cow += 1;
+    }
+  });
+
+  return obj;
+};
+
+module.exports = { check };
diff --git a/src/generateRandom.js b/src/generateRandom.js
new file mode 100644
index 0000000..1b79eb4
--- /dev/null
+++ b/src/generateRandom.js
@@ -0,0 +1,17 @@
+'use strict';
+
+function getRandomDigits() {
+  const digits = [];
+
+  while (digits.length < 4) {
+    const randomNumber = Math.floor(Math.random() * 10);
+
+    if (!digits.includes(randomNumber)) {
+      digits.push(randomNumber);
+    }
+  }
+
+  return digits.join('');
+}
+
+module.exports = { getRandomDigits };
diff --git a/src/guessValidation.js b/src/guessValidation.js
new file mode 100644
index 0000000..f8e6766
--- /dev/null
+++ b/src/guessValidation.js
@@ -0,0 +1,11 @@
+'use strict';
+
+const isValidGuess = (guess) => {
+  const arr = guess.split('');
+
+  const filtered = arr.filter((value, i) => arr.indexOf(value) === i);
+
+  return arr.length === filtered.length;
+};
+
+module.exports = { isValidGuess };
diff --git a/src/terminal.js b/src/terminal.js
new file mode 100644
index 0000000..7c6c304
--- /dev/null
+++ b/src/terminal.js
@@ -0,0 +1,10 @@
+'use strict';
+
+const readline = require('readline');
+
+const terminal = readline.createInterface({
+  input: process.stdin,
+  output: process.stdout,
+});
+
+module.exports = { terminal };