#include <stdio.h>

void rlencode(FILE* in, FILE* out)
{
	char curr, prev;
	unsigned char counter;
	
	while((curr = fgetc(in))!=EOF)
	{
		if(curr != prev){
			if (counter){
				fputc(counter, out);
				counter=0;
			}
			fputc(curr, out);
			prev = curr;
		}else{
			counter++;
			if(counter<=1)
				fputc(curr, out);
		}
	}
}

int main()
{
	FILE* input;
	FILE* output;
	
	input = fopen("input", "r");
	output = fopen("output", "w");
	
	rlencode(input, output);
	return 0;
}