#include <stdio.h>

typedef int bool;
#define true 0
#define false 1

int egyszam(int tomb[], int meret) {
	int i;
	int min = tomb[0];
	bool volt = false;
	for (i = 1; i < meret; i++) {
		if (tomb[i] < min) {
			volt = false;
			min = tomb[i];
		}
		else if (tomb[i] == min) {
			volt = true;
		}
	}

	if (volt == false) {
		return min;
	}
	return -1;

}

int main()
{
    int tomb[5] = { 2, 5, 6, 2, 4 };
    printf("%d\n", egyszam(tomb, 5));
    return 0;
}