#include <stdio.h>

#define P 0

#define N 1

int main () {
	char c;
	int stanje = P;
	int prelaz[2][2] = {{N,P}, {P,N}};
	while ((c=getchar())!=EOF && c!='\n') {
		if (c!='0' && c!='1') {
			printf("Greska:%c.\n",c);
			return -1;
		}
		stanje = prelaz[stanje][c-'0'];
	}
	if (stanje==P)
		printf("Prepoznata parna rec.\n");
	else
		printf("Nije prepoznata parna rec.\n");
	return 0;

}