cout<<"vvedi 1-e chislo"<<endl;
      int a;
      cin>>a;
      cout<<"vvedi 2-e chislo"<<endl;
      int b;
      cin>>b ;
      cout<<"wwedi 1 chtob naiti summu, 2 chtobi naiti raznicu, 3 dlya deleniya:"<<endl;
      int c;
      cin>>c;
      if(c== 1){
        cout<<a+b;
      }
      if(c== 2){
        cout<<a-b;
      }
      if(c== 3){
        cout<<a/b;
      }