Ответ:

#include <iostream>

using namespace std;

int main() {

   int A1, B1, C1, A2, B2, C2;

   cout << "Enter the dimensions of the first box: ";

   cin >> A1 >> B1 >> C1;

   cout << "Enter the dimensions of the second box: ";

   cin >> A2 >> B2 >> C2;

   if (A1 < A2 && B1 < B2 && C1 < C2) {

       cout << "The first box can be placed inside the second box." << endl;

   } else if (A1 < A2 && B1 < C2 && C1 < B2) {

       cout << "The first box can be placed inside the second box." << endl;

   } else if (A1 < B2 && B1 < A2 && C1 < C2) {

       cout << "The first box can be placed inside the second box." << endl;

   } else if (A1 < B2 && B1 < C2 && C1 < A2) {

       cout << "The first box can be placed inside the second box." << endl;

   } else if (A1 < C2 && B1 < A2 && C1 < B2) {

       cout << "The first box can be placed inside the second box." << endl;

   } else if (A1 < C2 && B1 < B2 && C1 < A2) {

       cout << "The first box can be placed inside the second box." << endl;

   } else {

       cout << "The first box cannot be placed inside the second box." << endl;

   }

   return 0;

}