// engarbage files

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

int main(int argc, char *argv[]) {
	time_t t;
	srand(time(&t));

	double rate = 0.5;
	if (argc > 1)
		rate = atof(argv[1]);
	for (int c = fgetc(stdin); c != EOF; c = fgetc(stdin)) {
		if ((double)rand() / (double)RAND_MAX < rate / 100)
			fputc(c + 1, stdout);
		else
			fputc(c, stdout);
	}
}