string frase,frase0;
		Console.WriteLine("Digite a frase: ");
		frase0 = Console.ReadLine();
		frase = frase0;	
		foreach(var a in frase0) {
     	    	if(a == 'a'){
     	    		frase.Replace(a, 'g');
     	    	}else if(a == 'b'){
     	    		frase.Replace(a, 'h');
     	    	}else if(a == 'c'){
     	    		frase.Replace(a, 'e');
     	    	}else if(a == 'd'){
     	    		frase.Replace(a, 'j');
     	    	}else if(a == 'e'){
     	    		frase.Replace(a, 'k');
     	    	}else if(a == 'f'){
     	    		frase.Replace(a, 'l');
     	    	}else if(a == 'g'){
     	    		frase.Replace(a, 'm');
     	    	}else if(a == 'h'){
     	    		frase.Replace(a, 'n');
     	    	}else if(a == 'i'){
     	    		frase.Replace(a, 'o');
     	    	}else if(a == 'j'){
     	    		frase.Replace(a, 'p');
     	    	}else if(a == 'k'){
     	    		frase.Replace(a, 'q');
     	    	}else if(a == 'l'){
     	    		frase.Replace(a, 'r');
     	    	}else if(a == 'm'){
     	    		frase.Replace(a, 's');
     	    	}else if(a == 'n'){
     	    		frase.Replace(a, 't');
     	    	}else if(a == 'o'){
     	    		frase.Replace(a, 'u');
     	    	}else if(a == 'p'){
     	    		frase.Replace(a, 'v');
     	    	}else if(a == 'q'){
     	    		frase.Replace(a, 'w');
     	    	}else if(a == 'r'){
     	    		frase.Replace(a, 'x');
     	    	}else if(a == 's'){
     	    		frase.Replace(a, 'y');
     	    	}else if(a == 't'){
     	    		frase.Replace(a, 'z');
     	    	}else if(a == 'u'){
     	    		frase.Replace(a, 'a');
     	    	}else if(a == 'v'){
     	    		frase.Replace(a, 'b');
     	    	}else if(a == 'w'){
     	    		frase.Replace(a, 'c');
     	    	}else if(a == 'x'){
     	    		frase.Replace(a, 'd');
     	    	}else if(a == 'y'){
     	    		frase.Replace(a, 'e');
     	    	}else if(a == 'z'){
     	    		frase.Replace(a, 'f');
     	    	}
     	   	}
     	    Console.WriteLine(frase);