# include <stdio.h>

int KeyGen(){
	int key;

	printf("Enter key: ");
	scanf("%d",&key);

	return key;
}



char Encrypt(char x, int key){
	char encrypt;

	if (x == '\0')
		return x;
	else 
		encrypt = x + key;
	return encrypt;
}


void main(void){
	char x,y;
	int key;
	FILE *Fin, *Fout;

	Fin = fopen("input.txt","r");
	Fout = fopen("output.txt","w");

	key = KeyGen();

	while (!feof(Fin)){
		fscanf(Fin,"%c",&x);
		y = Encrypt(x,key);
		fprintf(Fout,"%c",y);
	}
	fclose(Fin);
	fclose(Fout);
}