#include <stdio.h>

void main(void){
	int n = 0 ;
	scanf("%d",&n);
	char sleep[100000]  = "a"	;
	scanf("%s",sleep);
	int count = 0;
	int sleepList[n];
	for(int i = 1; i < n ; i++){
		if(sleep[i-1] == 'x' && sleep[i] == 'o'){
			sleepList[count] = i+1;
			count++;
		}
	}
	printf("%d\n",count);
	for(int i = 0 ; i < count ; i++){
		printf("%d",sleepList[i]);
		if(i != count -1){
			printf(" ");
		}
	}
}