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

int main()
{
	int N, renge = -1, count = 0, flag = 0;
	char* nya = (char*)"nyanpass", * hyphen = (char*)"-";
	char*** A;

	if (scanf("%d", &N) != 1) {
		return -1;
	}

	A = (char***)malloc(sizeof(char**) * N);

	if (A == NULL) {
		return -1;
	}

	for (int i = 0; i < N; i++) {
		*(A + i) = (char**)malloc(sizeof(char*) * N);

		if (*(A + i) == NULL) {
			return -1;
		}

		for (int j = 0; j < N; j++) {
			*(*(A + i) + j) = (char*)malloc(sizeof(char) * 101);

			if (*(*(A + i) + j) == NULL) {
				return -1;
			}

			if (scanf("%s", *(*(A + i) + j)) != 1) {
				return -1;
			}
		}
	}

	for (int i = 0; i < N; i++) {
		count = 0;
		for (int j = 0; j < N; j++) {
			if (strcmp(*(*(A + j) + i), nya) == 0 ||
				strcmp(*(*(A + j) + i), hyphen) == 0 ) {
				count++;
			}
		}

		if (count == N) {
			if (flag == 1) {
				renge = -1;
			}
			else {
				renge = i + 1;
				flag = 1;
			}
		}
	}

	printf("%d", renge);

	for (int i = 0; i < N; i++) {
		for (int j = 0; j < N; j++) {
			free(*(*(A + i) + j));
			*(*(A + i) + j) = NULL;
		}
		free(*(A + i));
		*(A + i) = NULL;
	}
	free(A);
	A = NULL;

	return 0;
}